Bio

Dr. Joshua O. Amimo (BVM, MS, PhD)

Joshua is a lecturer at the University of Nairobi (UoN) Kenya in the department of Animal Production Faculty of Veterinary Medicine teaching Animal Genetics and Breeding.Prior to his appointment at the UoN he was research technologist on livestock breeding strategies for low input production systems operating project at International Livestock research Institute (ILRI) in the project on Capacity Building for Sustainable Use of AnGR in the Developing Countries.

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Publications


2017

Vlasova, AN, Amimo JO, Saif LJ.  2017.  Porcine Rotaviruses: Epidemiology, Immune Responses and Control Strategies., 2017 Mar 18. Viruses. 9(3) Abstract

Rotaviruses (RVs) are a major cause of acute viral gastroenteritis in young animals and children worldwide. Immunocompetent adults of different species become resistant to clinical disease due to post-infection immunity, immune system maturation and gut physiological changes. Of the 9 RV genogroups (A-I), RV A, B, and C (RVA, RVB, and RVC, respectively) are associated with diarrhea in piglets. Although discovered decades ago, porcine genogroup E RVs (RVE) are uncommon and their pathogenesis is not studied well. The presence of porcine RV H (RVH), a newly defined distinct genogroup, was recently confirmed in diarrheic pigs in Japan, Brazil, and the US. The complex epidemiology, pathogenicity and high genetic diversity of porcine RVAs are widely recognized and well-studied. More recent data show a significant genetic diversity based on the VP7 gene analysis of RVB and C strains in pigs. In this review, we will summarize previous and recent research to provide insights on historic and current prevalence and genetic diversity of porcine RVs in different geographic regions and production systems. We will also provide a brief overview of immune responses to porcine RVs, available control strategies and zoonotic potential of different RV genotypes. An improved understanding of the above parameters may lead to the development of more optimal strategies to manage RV diarrheal disease in swine and humans.

Amimo, JO, Njuguna JN, Machuka E, Okoth E, Djikeng A.  2017.  First Complete Genome Sequence of Porcine Bocavirus Strains from East Africa. Genome Announcement.
Amimo, JO, Otieno TF, Okoth E, Onono JO, Bett B.  2017.  Risk factors for rotavirus infection in pigs in Busia and Teso subcounties, Western Kenya., 2016 Oct 08. Tropical animal health and production. 49(1):105–112. Abstract

We analysed data that were previously collected for molecular characterisation of rotavirus (RV) groups A and C in pigs from Teso and Busia subcounties in Kenya to determine risk factors for its infection. The data included records from 239 randomly selected piglets aged between 1 and 6 months raised in free range and backyard production systems. RV infection was confirmed by screening of fresh faecal samples by using reverse transcription polymerase chain reaction (RT-PCR); selected positive samples were subsequently sequenced and used for phylogenetic analysis. In this analysis, RV infection status was used as outcome variable, while the metadata collected at the time of sampling were used as predictors. A Bayesian hierarchical model which used integrated nested Laplace approximation (INLA) method was then fitted to the data. The model accounted for the spatial effect by using stochastic partial differential equations (SPDEs). Of the 239 samples screened, 206 were available for the analysis. Descriptive analyses showed that 27.7 % (57/206) of the samples were positive for rotaviruses groups A and C, 18.5 % were positive for group A rotaviruses, 5.3 % were positive for group C rotaviruses, while 3.9 % had co-infections from both groups of rotaviruses. The spatial effect was insignificant, and a simple (non-spatial) model showed that piglets (≤4 months) and those pigs kept in free range systems had higher risk of exposure to rotavirus infection as compared to older pigs (>4 months) and those tethered or housed, respectively. Intervention measures that will target these high-risk groups of pigs will be beneficial to farmers.

2016

Nyamwaya, D, Wang'ondu V, Amimo J, Michuki G, Ogugo M, Ontiri E, Sang R, Lindahl J, Grace D, Bett B.  2016.  Detection of West Nile virus in wild birds in Tana River and Garissa Counties, Kenya. BMC Infectious Diseases. 16:696.
Amimo, JO, El Zowalaty ME, Githae D, Wamalwa M, Djikeng A, Nasrallah GK.  2016.  Metagenomic analysis demonstrates the diversity of the fecal virome in asymptomatic pigs in East Africa. Archives of Virology. 161(4):887-897.

2015

Lawrence, FG, Mutembei HM, Lagat J, Mburu J, Amimo J, Okeyo AM.  2015.  Constraints to Use of Breeding Services in Kenya. International Journal of Veterinary Science. 4(4):211-215.
Thuo, DN, Junga JO, Kamau JK, Amimo JO, Kibegwa FM, Githui KE.  2015.  Population Viability Analysis of Black Rhinoceros (Diceros bicornis michaeli) in Lake Nakuru National Park, Kenya. Journal of Biodiversity and Endanger Species. 3:150.
Onono, JO, Amimo JO, Rushton J.  2015.  Constraints and efficiency of cattle marketing in semiarid pastoral system in Kenya. Tropical Animal Health and Production.
Amimo, JO, Junga JO, W. O. Ogara, Vlasova AN, Njahira MN, Maina S, Okoth EA, Bishop RP, Saif LJ, Djikeng A.  2015.  Detection and genetic characterization of porcine group A rotaviruses in asymptomatic pigs in smallholder farms in East Africa: Predominance of P[8] genotype resembling human strains.. Veterinary Microbiology. 175(2-4):195-210.

2014

Amimo, JO, Saif LJ, Junga J, Vlasova AN, Okoth EA, Njahira MN, Ogara WO, Djikeng A.  2014.  Detection and molecular characterization of selected swine enteric viruses in smallholder farms in Kenya and Uganda, 3-5 September. 9th Biennial Conference and exhibition of the faculty of Veterinary Medicine, University of Nairobi. , Upper Kabete Campus, Nairobidetection_and_molecular_characterization_of_selected_swine_enteric_viruses_in_smallholder_farms_in_kenya_and_uganda__9thbiennial_jamimo-18-08-2014_final.pdf
Marete, A, Mosi R, Amimo J, Junga J.  2014.  Characteristics of Lactation Curves of the Kenya Alpine Dairy Goats in Smallholder Farms. Open Journal of Animal Sciences. 4:92-102.
Amimo, JO, Okoth E, Owino JJ, Ogara WO, Njahira M, Vlasova AN, Saif LJ, Djikeng A.  2014.  Molecular detection and genetic characterization of kobuviruses and astroviruses in asymptomatic local pigs in East Africa. Archives of Virology. 159:1313-1319.

2013

Amimo, JO, Okoth EA, Junga JO, Ogara WO, Njahira MN, Vlasova AN, Saif LJ, Djikeng A.  2013.  Prevalence of rotaviruses in swine raised under small-scale production system in East Africa region. 2nd International Congress on Pathogens at the Human Animal Interface (ICOPHAI). , Porto de Galinhas, Recife Brazilprevalence_of_porcine_rotaviruses_in_east_africa_icophai__brazil_03-07-13_jamimo-16-07-2013-2.pdf
Maciel, S, Okeyo AM, Amimo J, Scholtz MM, Neser FWC, Martins M.  2013.  The effect of geographical region of birth on the reproductive performance of the Nguni in southern Mozambique. South African Journal Of Animal Science. 43(5 (1)):59-62.
Maciel, S, Amimo J, Martins M, Okeyo AM, Scholtz MM, Neser FWC.  2013.  Feedlot performance of the Nguni ecotypes in southern Mozambique. Livestock Research for Rural Development. 25(6):article111.

2012

OLUOCH, DRAMIMOJOSHUA.  2012.  Amimo JO, Vlasova AN and Saif LJ PREVALENCE AND GENETIC DIVERSITY OF GROUP A AND NON-GROUP A PORCINE ROTAVIRUSES IN SELECTED FARMS IN THE US. America Society of Virology conference. : America Society of Virology Abstract
Fecal samples collected in different seasons of 2004 and 2011 from diarrheic and healthy nursing piglets from 5 selected swine farms in the US were screened for group (Gp) A, B and C rotaviruses (RVs) using RT-PCR. RVs were identified in 27.4% (65/237) of the samples, with 7.6%, 1.3% and 21.5% positive for Gp A, B and C RVs, respectively. An increased prevalence of Gp A and C RVs was observed between 2004 (18%) and 2011 (37%), with the highest increase for Gp C (from 11.9% to 31.1%). Seasonal effects on the prevalence of Gp A and C RVs were observed within and between the 2 years with the highest in summer (35.2%) followed by winter (27.4%). The prevalence varied among the farms and since none of them used Gp A RV vaccines, we concluded that differences in management may influence RV prevalence. Partial sequencing and phylogenetic analysis of the VP6 gene of selected Gp C RVs from different farms revealed high nucleotide sequence identity with reference human (82.5-86%) and porcine (86.2-97.2%) Gp C RVs. Historic (2004) and recent (2011) Gp C strains from two farms shared high nucleotide identity between each other (97.2-99.5%) and clustered (>92% identity) with recent Korean (2009, G6 serotype) and Brazilian strains, however, a recent Gp C RV strain from another farm was distant from Cowden, Brazilian and Korean strains or the strains from other farms. Our preliminary data on Gp A RV genotyping (VP7 gene) indicate that there are multiple genotypes of Gp A RVs currently circulating in US swine. In conclusion, our study demonstrates that infection with distinct Gp C RVs is more frequent among nursing piglets than Gp A and B RV infections.

2011

OLUOCH, DRAMIMOJOSHUA.  2011.  Maciel, S, Amimo, J, Martins, M, Mwai, A, Scholtz, M and Neser, F Factors influencing reproductive performance of cows from different Nguni ecotypes in southern Mozambique. Tropical Animal Health and Production. : Tropical Animal Health and Production
OLUOCH, DRAMIMOJOSHUA.  2011.  Amimo J O, S Thumbi, B O Inyangala, J O Junga and R O Mosi (2011): Socio-economic characteristics and perceptions of cattle keepers and constraints to cattle production in Western Kenya. Livestock Research for Rural Development 23 (6) 2011. : Food and Agriculture Organization of the United Nations, 2011
OLUOCH, DRAMIMOJOSHUA.  2011.  I.S. Kosgey, S.M. Mbuku, A.M. Okeyo, J. Amimo, J. Philipsson and J.M. Ojango (2011) Institutional and organizational frameworks for dairy and beef cattle recording in Kenya: a review and opportunities for improvement. Animal Genetic Resources, 2011, 48, 1. : Food and Agriculture Organization of the United Nations, 2011 Abstract
SummaryTo facilitate livestock improvement in developing countries, records on animal populations and their various productivity levels are important. However, in these countries, livestock recording presents a huge challenge. This paper presents an outline of the historical developments and the current scenario in dairy and beef recording in Kenya, where a recording scheme has been in place since 1963, yet the productive potential of most animals in the country remains unknown. The paper brings into context the state of recording in relation to the potential for future developments in dairy and beef production within the country. Despite the enormous existing potential, low numbers of livestock records are captured due to multiple challenges, which include limited funding, lack of incentives to record, limited feedback on records, a fragmented organizational structure, poor infrastructure, limited numbers of skilled personnel and lack of supporting policies. Strategies to overcome the challenges and achieve more sustainable utilization of the existing livestock populations are discussed. Linking recording to key service providers within the livestock production sector could enhance data collection, processing and feedback to livestock producers. The quality of extension services provided must be improved in order to holisticallysupport livestock production. Recent international regulations on the traceability of livestock products sold within different countries mean that unless Kenya implements a robust animal recording programme, the country will be locked out of markets for its livestock products.

2009

Maciel, S;, Mwai OA;, Amimo JO;, Moyo S;, Scholtz M;, Neser F;, Martins M.  2009.  Environmental descriptors influencing performance of the Nguni ecotypes.
Fridah, L;G, Isabelle B;, Job L;, John M;, Henry M;, Joshua A;O, Okeyo AM.  2009.  A cost-benefit analysis of seced in-vitro fertilization embryo transfer in Kenya.

2007

Ojango, JMK;, Okeyo AM;, Amimo JO.  2007.  Livestock recording in developing countries: A case study from Kenya.
  2007.  An assessment of the efficiency of the dairy bull dam selection methodology in Kenya. Abstract

Data consisting of 5670 lactation records made by 2958 cows between 1990 and 2004 from 18 Ayrshire herds were used to evaluate the efficiency of the current bull dam selection method in Kenya. A univariate DF-REML procedure and the animal model with relationship was used to estimate Breeding Values (BVs) for unadjusted total lactation milk yield, as used by the current methodology. The mean milk yield was 4085 Kg with SD of 1396 Kg, and the breeding values (BVs) for milk yield for all the animals ranged from - 979 kg to + 1115 Kg. with a heritability of 0.18 ± 0.045. The BVs were then arranged in descending order and then ranked. Based on the unadjusted lactation records, the BVs for the top 100 cows ranged from +550 Kg to +1115 Kg. Only 25 of the 113 bull dams that were included in the study were ranked in the top 100 cows. The results indicate that there are a large number of cows in the national herd with high genetic merit that had been left out of the breeding programme using the current bull dam selection methodology and that cows with lower genetic merit have been used due to the inefficiency of the current bull dam selection method. Thus, the current method of bull dam selection is inefficient and needs to be improved by genetic evaluation of all the cows before bull dam selection

OLUOCH, DRAMIMOJOSHUA.  2007.  Amimo J O 2007 Production and reproductive performance of the Kenyan Ayrshire cattle. MSc Thesis, Department of Animal Production, University of Nairobi, Kenya. pp 73. MSc Thesis, Department of Animal Production, University of Nairobi, Kenya. pp 73. : Tropical Animal Health and Production

2006

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