PROF. KANGETHE ERASTUS KIAMBI

Antisera to thermostable muscle antigens from 13 wild animals: Buffalo, Waterbuck, Bushbuck, Eland, Oryx, Kongoni, Bushpig, Warthog, Topi, Thomson’s gazelle, Grant’s gazelle, Sheep, Pig, Horse, Camel & Dog, were raised in rabbits and/or goats. Absorptions of the antisera with copolymerized pooled serum from the 20 species and the thermostable muscle antigens rendered most of the antisera mmonospecific. It was possible to identify the species of origin of saline extracts of both cooked and fresh meat samples in immunodiffusion tests. The method is promising for use in identification of the species origin of fresh and cooked animal meats.

Raw and heat-treated pork and beef products were purchased from the outlets of two leading Kenyan manufacturing firms. Pure beef and pork sausages and pork sausages containing 1, 5 and 10% beef were prepared in the laboratory. Antigens from these products were extracted with phosphate buffered saline. The presence of beef and pork in these products was determined using absorbed goat antisera to cattle and pig thermostable muscle antigens in an enzyme immunoassay. The assay was able to detect beef in pork sausages at the level of 10% and 5% but not at 1%. Of the 44 commercial beef products labelled as containing only beef, 23 (52.3%) were shown to contain pork and 23 (50%) of the 46 pork products were shown to contain beef. Antisera to thermostable muscle antigens proved to be of great value in species identification not only of fresh unheated meats but also of heated (cooked, pasteurized and autoclaved) meat products in an enzyme immunoassay.

Antisera to thermosable muscle antigens (TMA) from 14 species of bovidae were raised in goats and/or sheep. To achieve species specificity the antisera were absorbed with serum from the other species. While the absorbed antisera to TMA to buffalo, impala, eland, waterbuck, wildebeest and oryx were rendered specific, the antiserum to cattle TMA cross-reacted with buffalo fresh meat antigens (FMA) and cooked meat antigens (CMA) but not with buffalo thermostable muscle antigens. Fresh and cooked muscle antigens from these two species could be differentiated by the antiserum to buffalo TMA. A similar approach was used to differentiate the FMA, CMA and TMA of kongoni, topi and wildebeest. Antiserum to cattle TMA proved useful in detecting the presence of beef meat in meat products that had undergone commercial sterilization.   Keywords: meat; meat products; thermostable muscle antitgens; immunodiffusion; antibodies; species identification

An enzyme immunoassay (EIA) suitable for use in identification of cooked and autoclaved meat samples using antisera to thermostable muscle antigens (TMA) is described. Goat antisera to TMA of various species were tested against homologous and heterologous partially purified thermostable muscle antigens (PTMA) in an indirect EIA. Goat anti-eland and anti-cattle TMA sera were the poorest in differentiating other species PTMAs. Identification of various species PTMAs could be achieved using a battery of goat anti-TMA sera, where homologous goat anti-TMA serum fails to differentiate some of the PTMAs tested.

A method for the extraction of thermostable muscle antigens for use in enzyme immunoassays is described. The method yields antigens devoid of contaminating proteins which reduce the adsorption of the antigens on to the plate. The effect of such proteins is stimulated by the addition of gelatin. Gelatin (5 mg ml-1) results in 100% inhibition of the antigen adsorption on to the plate.   Keywords: thermostable muscle antigens, enzyme immunoassay, meat species identification

Meat species identification has been necessitated by cases of unfair trading where label declarations are not met; in respect to the species of origin of the meat. Advantages and disadvantages of using polyacrylamide gel electrophoresis, isoenzyme and fat analysis in speciation of raw and cooked meat are presented. Isoelectic focusing of myoglobulin seems to be the only promising method which can be adopted for use in speciation of meat. However, more research work on myoglobulin assay is needed.

A preliminary study of microbiological quality of honey was carried out using 26 samples obtained from the National Bee Keeping Research Station. Total viable counts (TVC) of aerobic bacteria, yeasts and moulds, and Clostridium species were done. Of the 26 samples, 24 (92.3%) had a TVC ranging from 3 x10 -87 x 10 colony forming units (cfu) per gram of honey. Two samples did not yield any microorganisms. Of the 24 positive samples, 9 (37.5%) were found to contain Clostridium species per gram while eight (33.3%) were positive for moulds with counts ranging from 10-100 c.f.u / g. No yeasts were detected. In addition, three samples yielded the three types of microorganisms.

A review of the methods used for monitoring meat protein additives of fresh and cooked meats using physico-chemical and immunological methods is presented.

Tsetse polupations and trypanosome infections were monitored at the Ngulia Rhino Sanctuary to assess the impact of trypanosomiasis on rhinoceros. High densities of Glossina pallidipes were found near a permanent spring by the Ngulia escarpment; G. longipennis and G. brevipalpis were also present in lower numbers. Infection rates in G. pallidipes averaged 3.6%, with three times as many T. vivax as T. congolense infections. T. simiae and T. brucei were present at low frequency. DNA probes revealed that all mature T. congolense infections belonged to the savanna subgroup. G. pallidipes fed on many hosts, with most meals taken from bovides and elephants. Rhino account for one of the blood meals in a small sample taken from G. longipennis. During a time of low tsetse densities (dry season), we estimated that the wild host population was acquiring seven infections per km2 per day. At lower levels of challenge, an experimental rhino became infected with T. congolense. These results are discussed in terms of future plans for the repopulation of rhino in tsetse-infested areas in Kenya.   Keywords; epidemiology, disease, Glossina, parasitology, Trypanosoma

A survey of hygienic quality of bovine carcases from three slaugherhouses with different throughput and management was assessed using total viable counts and coliform counts from 5 sites (hindquarter, flank, brisk, forequarter and neck) on each carcass. The total viable counts showed that all three slaughterhouses were equally contaminated with bacteria exceeding 105 per cm2; the coliform counts revealed that contamination of the flank and brisket sites differed between slaughterhouses. Factors attributed to this level of contamination and their controls were discussed.

Inoculation of cystozoites obtained from natural, chronic cases of caprine besnoitiosis produced clinical disease in goats but not in rabbits, mice, guinea pigs, hamsters, rats or cattle. Histological examination of tissue sections from the experimental animals showed Besnoitia cysts only in goats. This, together with field observations that cattle reared together with goats having besnoitiosis do not contract the disease, suggests that the Besnoitia species that infects goats in Kenya is host-specific and is not Besnoitia besnoiti. We suggest that the name Besnoitia caprae be adapted for the pathogen.   Keywords; Besnoitia, clinical signs, conjuctiva, goats, infectivity, rabbits, rodents

A double antibody enzyme linked immunosorbent assay for identification of thermostable muscle antigens of autoclaved meat samples is described. The assay differentiates heterologous thermostable muscle antigens from homologous at P 0.001. In model meat mixtures, the assay detects adulterants at the level of 1% at p0.001 even in phylogenetically related species such as buffalo and cattle.

In total, 1,952 Glossina pallidipes Austen and 1,098 G. longipennis Corti adults were collected in forest and savanna habitat in Nguruman, southwestern G. pallidipes and many indicate that ostriches are an important host. More detailed work on the role of ostriches in the epidemiology of trypanosomiasis is required. Keywords; tsetse, blood source, enzyme-linked immunosorbent assay  

Comparative transmission electron microscopy on Besnoitia besnoiti and on a strain of Besnoitia derived from goats in Kenya revealed that the two organisms differ in their pellicle, micropore, microtubules, nucleus, wall-forming body 1 (W1), amount of lipids and amylopectin. Thus the caprine besnoitia is probably a different organism and the term Besnoitia caprae should continue to be used.   Keywords; Besnoitia besnoiti, Besnoitia caprae, cystozoite, goat, ultrastructure, speciation 

Cases of bovine cysticercosis in the carcasses, head and heart from different establishments were analyzed for the period between 1974 and 1991. national prevalence rates showed a dramatic decline from 8.8% in 1974 to 1.1% in 1991. Provvincial prevalence rates showed a decline in the cases reported within the same period. With the coast province having a decline from 45 in 1974 to 0.5% in 1991. Other provinces showed a similar trend in the decline of C. bovis cases. The impact of meat inspection has made on the control of bovine cysticercosis and new strategies for its control are discussed.

  Host blood effects on Trypanosoma congolense establishment in Glossina morsitans and Glossina morsitans centralis were investigated using goat, rabbit, cow and rhinocerous blood. Meals containing goat erythrocytes facilitated infection in G. m. morsitans, whereas meals containing goat plasma facilitated infection in G. m. centralis. Goat blood effects were not observed in the presence of complementary rabbit blood components. N-acetyl-glucosamine (a midgut lectin inhibitor) increased infection rates in some, but not all, blood manipulations. Cholesterol increased infections rates in G. m. centralis only. Both compounds together added to cow blood produced superinfection in G. m. centralis, but not in G. m. morsitans. Midgut protease levels didn’t differ 6 days post infection in flies maintaining infections versus flies clearing solutions. Protease levels were weakly correlated with patterns of infection, but only in G.m. morsitans. These results suggest that physiological mechanisms responsible for variation in infection rates are only superficially similar in these closely related tsetses.   Keywords; Glossina, Diptera, Glossinidae, Trypanosoma, lectis, proteases, goat, rabbit, cow, Diecros bicornis, choleastrol, glucosamine, erythocytes, serum

Five blue and black cloth traps designed for tsetse were tested for their ability to catch Stomoxys spp. in Kenya. Significantly greatest catches were obtained with Vavoua traps, which then were used to compare odor baits at Nairobi Park. Acetone, lactic acid and animal urine (cow, buffalo, waterbuck, camel) or dung (rhinoceros, elephant and hippopotamus) didn’t increase catches. However, 1-oceten-3-ol dispensed at 0.2-2.0 mg/h increased catches up to 3.7-fold. Vavoua traps were highly specific for Stomoxyinae, with 80% of the catch consisting of 11 different taxa of Stomoxys as well as genera such as Prostomoxys, Haematobosca, Stygeromyia and Rhinomusca. During periods of peak seasonal abundance, up to 3,000 Stomoxys per day were collected in an octenol-baited Vavoua trap. These high catches suggest that Vavoua traps may be of practical use for fly control in isolated settings at a relatively low cost.

Monthly meat inspection records for the period 1974-1991 were studied and reports of bovine cysticercosis in the carcasses, head and heart from different Provinces in Kenya were analysed. The national prevalence rate showed a dramatic decline from 8.8% in 1974 to 1.1% in 1991. Provincial prevalence rates showed a decline in the cases reported within the same period. The Coast Province showed a decrease from 4% in 1974 to 0.5% in 1991. Other provinces showed a similar trend. The impact meat inspection has made on the control of bovine cysticercosis and new strategies for its control are discussed.

Goats were injected with caseous pus containing 106 colony forming units CFU of C. pseudotuberculosis either subcutaneously (s/c), intradermally (i/d) or smeared with caseous pus on either scarified or intact skin. All animals were then examined regulary for clinical abnormalities and also for antibodies to C. pseudotuberculosis. All animals were sacrificed 10 weeks after infection and examined for caseous lymphadenitis (CLA) lesions.  Acute lameness was observed in all animals infected s/c but not in the other groups. The regional draining lymph nodes were detected palpably swollen by day three post infection in all animals infected i/d and in one infected on scarified skin. The route of infection did not influence the onset of serological response but animals infected i/d had more rapid and higher response. At post mortem, animals infected s/c; i/d or on scarified skin had abscesses in the regional draining lymph nodes but those infected on intact skin had none. These results indicted that CLA can be transmitted through either s/c, i/d or through scarified skin but that infection through intact skin was unlikely. The disease induced by i/d injection or on scarified skin was more typical of the natural disease in that it had no acute clinical signs.

Group B streptococci (GBS) were isolated from bovine bulk milk and from vaginas and throats of antenatal and postnatal women using TKT and rapid GBS media. Sixty three of 529 (12%) bovine milk samples, 9 of 48 (19%) vaginal and 3 of 48 (6%) throrat samples were positive. Both bovine and human beta hemolytic isolates were characterized biochemically and serologically. Pigment production was characteristic of both human and bovine beta haemolytic isolates. The majority (88%) of human isolates fermented salicin and not lactose and most bovine isolates were either lactose positive/salicin positive (41%) or lactose positive/salicin negative (38%). Human and bovine isolates were 100% and 85% typable respectively. Serotype distribution was similar in the bovine and human populations with serotype Ia, Ic and III being most common in both. Fermentation of sugars showed major differences between bovine and human isolates but similarity in serotype distribution suggests some genetic relationship.

This paper describes the methodology and some results obtained from an integrated assessment of smallholder dairy farms in Kiambu District Kenya, using the agro-ecosystem health approach. Participatory techniques, soft system methods, complex system theory and convectional research are used in combination. The approach is holistic, multidisciplinary and iterative. It involves designing, planning, implementation, monitoring and evaluation of the development processes. The aim is to make smallholder dairy farms sustainable. A sustainable agricultural system is one in which resource management is optimized to satisfy changing human needs while maintaining or enhancing the quality of the environment and its capacity. The approach applies the agro-ecosystems concepts of health developed both in veterinary and human health. Screening diagnosis and remediation of ecosystems pathologies are carried out in methods analogous to those in individuals and populations.

Goats were infected intradermally with caseous pus containing between 1x105 and 5x101 colony forming units (CFU) of Corynebacterium pseudotuberculosis. Animals infected with doses of equal and above 1x105 CFU of the organism developed caseous lesions in the regional draining lymph nodes. On serological examination, 3/6 animals infected with equal or less than 1x101 CFU and 2/4 infected with equal or less than 1x102 CFU had no positive bacterial agglutination and antitoxin antibody titres respectively. These results indicated that caseous lymphadenitis (CLA) is a highly contagious disease since relatively low doses (1x102 CFU) of C.pseudotuberculosis injected intradermally could induce CLA lesions in draining lymph nodes. The serological response in terms of rate and extent appeared to depend on the dose of infection.

Goats were infected intradermally with caseous pus containing between 1x105 and 5x101 colony forming units (CFU) of Corynebacterium pseudotuberculosis. Animals infected with doses of equal and above 1x105 CFU of the organism developed caseous lesions in the regional draining lymph nodes. On serological examination, 3/6 animals infected with equal or less than 1x101 CFU and 2/4 infected with equal or less than 1x102 CFU had no positive bacterial agglutination and antitoxin antibody titres respectively. These results indicated that caseous lymphadenitis (CLA) is a highly contagious disease since relatively low doses (1x102 CFU) of C.pseudotuberculosis injected intradermally could induce CLA lesions in draining lymph nodes. The serological response in terms of rate and extent appeared to depend on the dose of infection.

There is an increasing need to incorporate into agricultural research an element of community participation. Community involvement in the identification of problems and solutions is seen as the key to adoption ands adaptation of new technologies. These two processes have been identified as crucial for sustainable agriculture and hence sustainable rural communities.

A wide gap exists between researchers in the various institutions and the farmer. Yet the latter is the end user of the products thereof. This is an approach to the top-down approach to agricultural extension where extension agents tell farmer's what ought to be done with little regard to the farmers experience and circumstances. Participatory action research (PAR) techniques bridge the gap between the farmer's experiences and the research/extension services. It enables analysis of problem situations and opportunities by farmers and researchers in a participatory and inclusive process. Within the agro-ecosystem health framework PAR is the process that generates a farmer driven demand for research and technology development. This paper describes how PAR is being used in an integrated assessment of agricultural communities in Kiambu agro-ecosystem.

Sustainability in agriculture requires a better understanding of interactions within the production syatem. Diverse factors such as social structure, knowledge and information flow all as well as other bio[hyscical afctors interact with each other to determine agricultural productivity and sustainability. Researchers and extension agents find that they need to deal with issues that may be outside their area of specialization. An interdisciplinary approach provides a framework through which such support can be provided.

Experimental transmission of Besnoitia caprae from naturally infected goats to susceptible ones was achieved by intra-nasal instillation and intra-conjuctival inoculation of cystozoites containing suspensions, subcutaneous implantation of fascia containing cysts and alternate needle pricking between infected and non infected goats. Typical chronic symptoms developed in the fascia infected does.Cystozoites inoculation into the eyes and mouth did not result in infection in utero, suggesting that intra-uterine transmission may not occur. In contrast to does with acute besnoitiosis, which occasionally aborted, the does with chronic besnoitiosis gave birth to healthy kids. Kids below the age of 4 months (pre-weaned period) born both to infected and non infected does were susceptible to besnoitiosis but appeared to be more resistant than adult goats.

A preliminary survey of besnoitiosis in domestic ruminants in Kenya based on field and farm visits, clinical and post mortem examinations and histopathological of tissues and biopsies showed that goats are the most affected followed by cattle, while sheep were unaffected. Caprine besnoitiosis occurred in a continuous belt in five of the 8 provinces in Kenya stretching from the Coast, Eastern, North Eastern, Nairobi and Rift Valley provinces.  Mandera in the North Eastern province had the highest prevalence rate of 36%, followed by Kwale 35%, Isiolo 35% Marsabit 33%, Wajir 28%, Nairobi 265 Meru 24%, Garissa 21% Taita Taveta 18%, Embu 17%, Kitui 9%, Machakos 7%, Laikipia 3% Kajiado 2% and Turkana and Elgeyo- Marakwet 1% each. There was no significant difference (P≤0.05) between the bucks and does (18 and 18.4% respectively), but kids were less (4%) affected. Bovine besnoitiosis was found only in Tana River district with an infection rate of 11%.

Cases of bovine hydatidosis in the livers and lungs at post mortem from different establishments in Kenya were analyzed for the period between 1974 and 1991. The results showed a significant difference in the condemnation rates of lungs between provinces (P=0.0001) and a decline per year of 0.4% though this was not statistically significant (P=0.4). The condemnation rates of livers showed a significant difference between the provinces (P=0.0001) with a decline of 2.3%. It was only in the Rift valley province where condemnation rates for both organs did not show a decline, but instead a significant increase was observed. Other provinces had significant declines indicating that the meat inspection and condemnation of infected organs had an impact in the control of hydatidosis. Overviews of the strategies for the control of hydatidosis in Kenya are discussed.

Despite policies to discourage them, informal milk markets account for over 80% of milk sales in most sub-Saharan African (SSA) countries. Informal milk market agents include farmer dairy co-operatives, small traders using bicycles and public or private transport and small retail outlets, such as dairy kiosks, and shops. Studies conducted by the International Livestock Research Institute (ILRI) and national collaborators (e.g., in Kenya1) show that convenient delivery and lower prices (reflecting lower handling and processing costs) are the principal benefits for consumers. Current milk handling and safety regulations in most SSA countries are derived from models in industrialised countries. These may not be appropriate for local market conditions where such regulations may unnecessarily inhibit efficient milk marketing. An important step in developing targeted policies more supportive of market participation of the majority is to collect quantitative and qualitative information about milk-borne health risks under different production and marketing situations. This paper gives an over-view of on-going activities in central Kenya aimed at assessing public health risks from informally marketed milk and presents preliminary results of milk quality and handling practices of informal milk market agents and consumers

The risk of infection by milk-borne brucellosis is one reason for public health regulations which discourage informal milk markets that sell unpasteurized milk. However, these regulations are not generally implemented in many developing countries. Kenya is a typical example, with over 85% of milk sales passing through informal channels. Consumer practices to reduce or eliminate potential infection by milk-borne health hazards under these circumstances have rarely been studied. Seasonal survey data were collected between January 1999 and January 2000 from informal milk market agents of various cadres and from households consuming unpasteurized milk in rural and urban locations in central Kenya. Respondents were randomly selected within production system (extensive and intensive) and human population density (urban, peri-urban and rural) strata. In addition, pasteurized and packaged milk samples from five processors were collected. Samples were screened for antibodies to Brucella abortus using the milk ring test (MRT) (unpasteurized milk) and indirect antibody ELISA (both unpasteurized and pasteurized milk). Milk samples originating from farms in the extensive production system and those containing milk from many sources were associated with higher antibody detection proportions. Five percent of all raw milk samples collected from consumer households and 4% of samples collected from various levels of bulking of market samples were positive to the ELISA. There was poor to no agreement between the two antibody detection tests. All urban consumers and 96% of rural consumers of unpasteurized milk indicated that they boil the milk (in tea or otherwise) before consumption. The implications of these results on milk marketing in Kenya are discussed.

E. coli 0157:H7 is a newly recognised bacterial zoonosis that originates from the gut of infected cattle. It causes potentially fatal haemorrhagic enteritis, haemolytic uraemic syndrome and kidney damage in humans. Epidemiological data on E. coli 0157:H7 infection and transmission in developing countries remain scarce but it is suspected that consumption of unpasteurised milk is an important vehicle for its transmission to humans, as milk can easily be contaminated with cattle faeces during milking. Given the high proportion of informal sales of unpasteurized milk in many tropical countries, E. coli 0157:H7 has been one of several zoonoses of concern. Between January 1999 and January 2000, survey data and raw milk samples were collected seasonally from households consuming unpasteurised milk in rural and urban locations in central Kenya. Respondents were randomly selected within production system (extensive and intensive) and human population density (urban, peri-urban and rural) strata. Laboratory samples were assessed for bacteriological quality by total and coliform counts. Selective media were used sequentially to screen for faecal coliforms and E. coli 0157:H7. Suspect E. coli 0157:H7 colonies were also serotyped and tested for production of verocytotoxins. E. coli was recovered from 91 out of 264 samples (34%) and E. coli 0157:H7 serotype identified in two samples (<1%). One of the two isolates produced verocytotoxins. As in many studies, the recovery rate of this serotype was low, but the finding is significant from a public health perspective. Our consumer studies have shown that over 95% of consumers of unpasteurised milk boil the milk before consumption and potential health risks from this zoonosis are therefore quite low. As informal milk markets without pasteurisation technology are likely to remain dominant for the foreseeable future, there is the need to further emphasise the importance of boiling raw milk before consumption, especially among pastoral communities where this practice is not common.

Twenty goats in two groups of 10 were injected intradermally, with Corynebacterium pseudotuberculosis. The doses of infection were 1x105 and 5x104 colony forming units for groups 1 and 2 respectively. Thereafter, a goat from each group was killed every 2-3 days and examined for gross and microscopic caseous lesions in the draining lymph nodes. Bands or zones of macrophages and polymorphonuclear granulocytes were observed on the second day of infection in both groups. Gross caseous lesions were observed from day 8 and 9 of infection respectively. Positive bacterial agglutination test and haemolysin inhibition test titres were detected after 15-17days and 20 -25 days of infection respectively. These results indicated that caseous lymphadenitis is a subacute disease with an incubation period of 8-9 days but it is not detectable serologically until after 15 days of infection.

{ An ante-mortem antigen ELISA based diagnosis of Taenia saginata cysticercosis was studied in artificially (n=24) and naturally (n=25) infected cattle with the objective of further validating the assay as a field diagnostic test. Based on total dissection as the definitive method of validity, the assay minimally detected 14 live cysticerci in artificially infected calves and 2 in natural infected steers. In natural infections, the minimum number of live cysticerci consistently detected by Ag-ELISA was 5 while in artificially infected calves it was above14. However, other animals with 12 and 17 live cysticerci in artificially infected calves and 1 and 2 in naturally infected steers escaped detection for unknown reasons. Animals harboring dead cysticerci gave negative results in the assay as were the case in non infected experimental control calves. There was a statistically significant positive linear correlation between Ag-ELISA optical density values and burdens of live cysticerci as obtained by total dissection of both artificially and natural infected calves (r=o.798

The major role played by informal milk markets in Kenya and the benefits to those associated with it are now widely acknowledged. The benefits include higher prices for farmers, income generation for the market agents and convenient delivery and lower prices for poor consumers. However, in spite of these benefits, regulations governing informal marketing of milk continue to be unfavourable and do not reflect local realities of milk marketing, having been based on models derived from industrialised countries where virtually all milk destined for the market is pasteurised and packaged. Results of risk assessment, including HACCP analysis, of milk quality and handling practices of informal milk market agents and consumers in central and southern Kenya show variable apparent prevalence of zoonotic health hazards in marketed milk, high bacterial counts especially in outlets associated with longer market chains. Notably, the ineffectiveness of current regulations was reflected in the lack of difference in the quality of milk sold by licensed and non-licensed traders. The study shows that health risks from the bacterial hazards identified are mitigated by the common consumer practice of boiling milk before consumption. The most important health risks were judged to be from two main sources: (i) anti-microbial residues found in up to 15% of milk samples tested and (ii) consumption of naturally fermented milk. Proposals for management of these health risks and the engagement of stakeholders and key players in the process to achieve more favourable policy environment policy are presented and discussed.

A total of 55 cattle divided into two groups of experimentally (n=30) and naturally (n=25) infected animals were used to study the reliability of meat inspection methods in Kenya. Total dissection was used as the gold standard to indicate absence or presence of bovine cysticercosis infection in cattle. The level of agreement between the two methods was on average lower in naturally infected animals than in artificially infected calves. This was because in natural infections, there was more light infections than in experimentally infections and these could not be detected in meat inspection method. The results further confirm that in spite of the time and effort taken by meat inspectors in looking for cysticerci at predilection sites, this method is very insensitive. It was therefore recommended that more parts of the carcass not naturally inspected according to the Kenya Meat Control Act (cap 356 of 1977) for bovine cysticercosis such as the lungs, hind legs, ribs and liver need to be considered as possible and equally important predilection sites and larger areas of these predilection sites should be examined. However, other better sensitive ante-mortem diagnostic methods should be developed to assist in the integrated management of the infection.

Existing physicochemical analytical methods for the determination of aflatoxins in animal tissues are expensive, cumbersome, and hazardous. To offer an alternative to these methods, a novel and highly sensitive immunochemical method for the rapid detection of aflatoxin B1 (AFB1) in chicken liver tissues is described in this study. Liver tissues were homogenized with cold methanol-acetone (50:50), followed by AFB1 extraction with methanol-acetone-PBS (25:25:50). The tissue extracts were, with or without further purification by immunoaffinity chromatography (IAC), applied to a highly sensitive direct ELISA for determination of AFB1. The detection limits for this assay were 15 +/- 0.77 pg/mL when standards and samples were dissolved in methanol-PBS (10:90) and 17 +/- 2.0 pg/mL when methanol-acetone-PBS (5:5:90) solution was used. The average recoveries of AFB1 were 54.3 to 65.5% in artificially contaminated tissue samples at 1 to 5 ng/g. In samples spiked with AFB1 at 1 ng/g, the method had diagnostic sensitivity and specificity of 100% for samples processed with IAC and 91.7 and 100%, respectively, for samples without IAC purification. The test was successfully applied to the detection of AFB1 in liver tissues from chickens that were experimentally dosed with AFB1. It is hoped that this test will be applicable in rapid detection of aflatoxins in poultry meats and in diagnosis of aflatoxicosis in chicken.

Despite an unfavorable policy environment against informal milk markets, these market account for most milk sales in Kenya. Convenient delivery and lower prices are the principal benefits for poor consumers. Current milk handling and safety regulations in Kenya are derived from models in industrialized countries. These may not be appropriate for local market conditions. An important step in targeting policies better is to collect quantitative and qualitative information about milk-borne health risk under different market situations. Preliminary results of assessments of milk quality and handling practices of informal milk market agents and consumers in central Kenya show very low apparent prevalence of zoonotic health hazards in milk from smallholder herds o[that contribute most marketed milk. Higher bacterial counts were associated with longer market chains and distance to urban areas. Most (up to 80%) of samples did not meet national bacterial quality standards. Over 96% of consumes boiled milk before consumption mainly to lengthen shelf life but also for health reasons. The most important health risks were judged to be from antimicrobial residues found in up to 16% of milk samples tested.

Over 85% of all milk sales on Kenya pass through informal channels. The extent of the risk posed by the sale of this raw milk to human health in respect to brucellosis is unknown. This paper presents the results of a study on the occurrence of antibodies to Brucella abortus in milk from households consuming raw unpasteurized milk and market agent selling the same. Four hundred thirty four (434) raw milk samples from consumer households and 508 from informal market agents were collected between January 1999 and January 2000 from Nakuru /Narok and Nairobi/Kiambu. Milk agents sampled included co-operative societies, milk collecting centers and self-help groups, milk bars, shops and kiosks and mobile traders on foot, bicycle or motorized transport. In addition, 147 samples from the formal market chain (pasteurized) were collected. All the samples from the samples were screened for antibodies to Brucella abortus using ELISA and Milk Ring Test (MRT), except for the formal milk that was tested using ELISA only. Five percent of the consumer household samples and 4% of the samples form informal milk market agents tested positive on ELISA. There was poor agreement between the two antibody surrogate tests (Kappa =0.40, 95% confidence interval =0.19-0.60). ELISA detected 3.2% more samples from consumer households and 0.4% from informal market agents than MRT. Of the formal market samples, 16.4% were positive. Ways of reducing the risk of contracting brucellosis from drinking raw milk are proposed.

As part of a study to assess zoonotic milk-borne health risks, seasonal survey data and unpasteurized milk samples were collected between January 1999 and February 2000 from randomly selected informal milk market agents (220 and 236 samples in the dry and wet seasons, respectively) and from households purchasing raw milk (213 and 219 samples in the dry and wet seasons, respectively) in rural and urban locations in Central Kenya and screened for antibiotics, Brucella abortus (B. abortus) and presence of Escherichia coli (E. coli 0157:H7).The latter was assessed based on samples from consumer households only. Antibodies to B. abortus were screened using the indirect antibody Enzyme Linked Immunosorbent Assay (ELISA) and the Milk Ring Test (MRT). The presence of E. coli 0157:H7 was assessed by culture, biochemical characterization, serological testing for production of verocytotoxin one (VTI) and two (VT2) and polymerase chain reaction (PCR) analysis for the presence of genes encoding for the toxins.                                                                                                         The prevalence of antibodies to B.abortus varied considerably ranging from none in milk sold in small units and originating from intensive production systems to over 10% in samples that were bulked or originating from extensive production systems. E. coli 0157:H7 was isolated from two samples (0.8%), one of which produced VTI. All urban consumers (100%) and nearly all rural consumers (96%) of marketed milk boiled the milk before consumption, mainly in tea, thus reducing chances of exposure to live pathogens and potential health risks.

To estimate the prevalence of Aflatoxin M1 and Total Aflatoxin B1 in milk and animal feeds. Cross sectional household study. Urban and peri-urban area of Dagoretti Division, Nairobi, Kenya. Two hundred fifty seven dairy farming households and 134 non-dairy neighbouring households. The prevalence of AFM1 in milk was found to be 45.5% (178/391). The farmer prevalence was 43.5% (112/257), while that of non-farmer was 49.2% (66/ 134). There was however no statistical significant difference between the two categories. Of the 178 positive milk samples, 49% had aflatoxin levels exceeding 0.05 microg Kg(-1). The prevalence of AFB1 in the feed was found to be 98.6% (69/70) with 83% of the samples having aflatoxin B1 levels exceeding 10 microg Kg(-1). Only one feed sample had no traces of AFB1. This study points to an underlying problem that requires the action by policy makers, considering the number of samples with aflatoxin M1 [49%] and aflatoxin B1 [83%] exceeding the WHO/FAO tolerance limits for milk and feeds destined for dairy animals.

The objective of the study was to identify Cryptosporidium genotypes from feces collected from urban and peri-urban dairy cattle in Nairobi, Kenya, in order to determine their zoonotic potential. DNA was extracted from 34 samples that were diagnosed positive by the modified Ziehl–Neelsen technique. Two Cryptosporidium isolates examined at the 18S rRNA locus were identified as the deer-like genotype by DNA sequencing. As public health officials are facing the difficult decision whether to allow urban livestock production because of its economic benefits and a livelihood asset to the urban communities, or to ban it for its public health risks, the finding of non-zoonotic genotypes in a smallholder dairy system has significant public health as well as economic implications that merit further investigation

Cryptosporidium was conducted with 20 farmers randomly selected from the 29 farmers in the wider survey who were considered at high risk because of farming system. We found that around 1 in 80 urban households kept dairy cattle with an average of three cattle per household. Cross-breeds of exotic and local cattle predominate. Heads of dairykeeping households were significantly less educated than the heads of non-dairy neighbours, had lived in Dagoretti for significantly longer and had significantly larger households. There was a high turnover of 10 % of the cattle population in the 3-month period of the study. Cattle were zero grazed, but productivity parameters were sub-optimal as were hygiene and husbandry practices. In conclusion, dairy keeping is a minor activity in urban Nairobi but important to households involved and their community. Ecohealth approaches are well suited to tackling the complex problem of assessing and managing emerging zoonoses in urban settings. Keywords Urban dairy . Cryptosporidiosis . Ecohealth . Kenya

The objective was to determine the antimicrobial susceptibility of the non-sorbitol fermenting Escherichia coli colonies from cattle feaces and milk samples collected from Dagoretti division in Nairobi. A total of 285 feacal and 260 milk were collected from urban dairy farming households while non-dairy households provided 137 milk samples. The samples were used for culture and isolation of E. coli and the colonies isolated using standard microbiological methods. 23% (66) and 8.8% (23) of feacal and milk samples from urban dairy farming households had non sorbitol fermenting colonies, while 8.8% (12) of non-dairy farming household neighbours had non sorbitol fermenting colonies in milk samples. Antibiotic susceptibility patterns showed that isolates of E. coli were resistant to various antibiotics. There was a high percentage resistance to sulphamethoxazole in feacal samples isolates (14.4%), milk sample isolates (10%) from dairy farming household and milk sample isolates (11.7%) nondairy households. The feacal isolates had a low resistance to ampicilin (1.4%), but the resistance in isolates from milk samples of urban dairy household (6.5%) and non-dairy household’s milk samples (7.3%) were high. The other antibiotics showed varied resistance pattern with feacal isolates having a high percentage resistance to tetracyclines (6.7%) while most bacterial isolates were susceptible to gentamicin. Multiple antibiotic resistances was observed in feacal sample isolates (6.7%), dairy farming household milk isolates (4.2%) and non- dairy farming household milk isolates (7.3%). Non-sorbitol fermenting E. coli colonies from cattle feaces and milk samples were resistant to most of the antibiotics tested and the higher percentage resistance to sulphamethoxazole, ampicilin and tetracyclines requires further investigation to isolate, identify and compare the genes responsible for development of resistance.

Zoonoses occur at the interface of human and animal disease and partly because their impact and management fall across two sectors they are often neglected. The Global Burden of Disease captures the impact of zoonoses on human health in terms of disability-adjusted life years (DALYs). Based on this, we estimate that in low income countries, zoonoses and diseases which recently emerged from animals make up 26 % of the DALYs lost to infectious disease and 10 % of the total DALYs lost. In contrast, in high income countries, zoonoses and diseases recently which emerged from animals represent less than 1 % of DALYs lost to infectious disease and only 0.02 % of the total disease burden. We present a framework that captures the costs of zoonoses and emerging disease to human, animal and ecosystem health in terms of cost of treatment, cost of prevention, health burden and intangible and opportunity costs. We also discuss how ecohealth concepts of transdisciplinarity, participation and equity can help in assessing the importance of zoonoses in developing countries and illustrate these with an example of assessing milk-borne disease.

The aim of the study was to investigate the social and gender determinants of the risk of exposure to Cryptosporidium fromurban dairying in Dagoretti, Nairobi. Focus group discussions were held in six locations to obtain qualitative information on risk of exposure. A repeated cross-sectional descriptive study included participatory assessment and household questionnaires (300 randomly selected urban dairy farming households and 100 non-dairying neighbours). One hundred dairy households randomly selected from the 300 dairy households participated in an additional economic survey along with 40 neighbouring non-dairy households. We found that exposure to Cryptosporidium was influenced by gender, age and role in the household. Farm workers and people aged 50 to 65 years had most contact with cattle, and women had greater contact with raw milk. However, children had relatively higher consumption of raw milk than other age groups. Adult women had more daily contact with cattle faeces than adult men, and older women had more contact than older men. Employees had greater contact with cattle than other groups and cattle faeces, and most (77 %) were male. Women took more care of sick people and were more at risk from exposure by this route. Poverty did not affect the level of exposure to cattle but did decrease consumption of milk. There was no significant difference between men and women as regards levels of knowledge on symptoms of cryptosporidiosis infections or other zoonotic diseases associated with dairy farming. Awareness of cryptosporidiosis and its transmission increased significantly with rising levels of education. Members of nondairy households and children under the age of 12 years had significantly higher odds of reporting diarrhoea: gender, season and contact with cattle or cattle dung were not significantly linked with diarrhoea. In conclusion, social and gender factors are important determinants of exposure to zoonotic disease in Nairobi.