pathogens Brief Report
First Detection of Rotavirus Group C in Asymptomatic Pigs of Smallholder Farms in East Africa Joshua Oluoch Amimo 1,2, * 1 2
*
ID
, Eunice Magoma Machuka 2 and Edward Okoth 2
Department of Animal Production, Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, Nairobi 00625, Kenya Biosciences of East and Central Africa-International Livestock Research Institute, (BecA-ILRI) Hub, P.O. Box 30709, Nairobi 00100, Kenya; [email protected] (E.M.M.); [email protected] (E.O.) Correspondence: [email protected]
Received: 10 July 2017; Accepted: 11 August 2017; Published: 14 August 2017
Abstract: Group C rotavirus (RVC) has been described to be a causative agent of gastroenteritis in humans and animals including pigs, cows, and dogs. Fecal samples collected from asymptomatic pigs in smallholder swine farms in Kenya and Uganda were screened for the presence of group C rotaviruses (RVC) using a reverse transcription-polymerase chain reaction assay. A total of 446 samples were tested and 37 were positive (8.3%). A significantly larger (p < 0.05) number of RVC-positive samples was detected in groups of older pigs (5–6 months) than in younger piglets (1–2 months). There were no significant differences in the RVC detection rate between the pigs that were full time housed/tethered and those that were free range combined with housing/tethering. After compiling these data with diagnostic results for group A rotaviruses (RVA), 13 RVC-positive samples were also positive for RVA. This study provides the first evidence that porcine group C rotavirus may be detected frequently in asymptomatic piglets (aged < 1–6 months) in East Africa. The occurrence of RVC in mixed infections with RVA and other enteric pathogens requires further research to investigate the pathogenic potential of RVC in pigs. Keywords: smallholder pigs; rotavirus group C; East Africa
1. Introduction Smallholder pig producers own the bulk of the pigs (>80%) in sub-Saharan Africa, and present the strongest influence to the swine industry in this region. These smallholder farms are characterized by low productivity compared to larger scale commercial farms in developed countries. The major constraints hampering the growth and development of the pig industry in the region is the high disease burden. In developing countries, one of the major causes of mortality among children ( 0.05), however, the prevalence was slightly higher in the piglets that were free range combined with tethering or housing (9.6%) compared with the piglets that were fully tethered or housed (7.3%). The study examined the effect of the herd size on the prevalence of RVC, and found that piglets in a herd of 6–10 pigs (10.8%) were more affected. Based on the month of sample collection, there was high prevalence of RVC in July (11.8%) and November (10.5%), however, there was no evidence of seasonal influence on RVC prevalence in the study region, since July is in the dry season and November is in the short rainy season. Nonetheless, we recommend a comprehensive study to elucidate the seasonal influence on RVC prevalence in the study area. The prevalence reported here was lower than the 19.5% reported in the USA [6], 26.3% reported in S. Korea (Jeong et al., 2009), and 28.7% reported in Italy (Martella et al., 2007). However, the previous studies in Korea and Italy analyzed only samples from diarrheic pigs, whereas we used samples from non-diarrheic pigs. The study by Amimo and colleagues in the USA examined fecal samples from both symptomatic and asymptomatic piglets, and reported an overall porcine RVC prevalence of 19.5% with 8.5% in asymptomatic weaned pigs in USA, which is consistent with our results. The study reported high RVC prevalence (23.5%) in younger piglets (
First Detection of Rotavirus Group C in Asymptomatic Pigs of Smallholder Farms in East Africa Joshua Oluoch Amimo 1,2, * 1 2
*
ID
, Eunice Magoma Machuka 2 and Edward Okoth 2
Department of Animal Production, Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, Nairobi 00625, Kenya Biosciences of East and Central Africa-International Livestock Research Institute, (BecA-ILRI) Hub, P.O. Box 30709, Nairobi 00100, Kenya; [email protected] (E.M.M.); [email protected] (E.O.) Correspondence: [email protected]
Received: 10 July 2017; Accepted: 11 August 2017; Published: 14 August 2017
Abstract: Group C rotavirus (RVC) has been described to be a causative agent of gastroenteritis in humans and animals including pigs, cows, and dogs. Fecal samples collected from asymptomatic pigs in smallholder swine farms in Kenya and Uganda were screened for the presence of group C rotaviruses (RVC) using a reverse transcription-polymerase chain reaction assay. A total of 446 samples were tested and 37 were positive (8.3%). A significantly larger (p < 0.05) number of RVC-positive samples was detected in groups of older pigs (5–6 months) than in younger piglets (1–2 months). There were no significant differences in the RVC detection rate between the pigs that were full time housed/tethered and those that were free range combined with housing/tethering. After compiling these data with diagnostic results for group A rotaviruses (RVA), 13 RVC-positive samples were also positive for RVA. This study provides the first evidence that porcine group C rotavirus may be detected frequently in asymptomatic piglets (aged < 1–6 months) in East Africa. The occurrence of RVC in mixed infections with RVA and other enteric pathogens requires further research to investigate the pathogenic potential of RVC in pigs. Keywords: smallholder pigs; rotavirus group C; East Africa
1. Introduction Smallholder pig producers own the bulk of the pigs (>80%) in sub-Saharan Africa, and present the strongest influence to the swine industry in this region. These smallholder farms are characterized by low productivity compared to larger scale commercial farms in developed countries. The major constraints hampering the growth and development of the pig industry in the region is the high disease burden. In developing countries, one of the major causes of mortality among children ( 0.05), however, the prevalence was slightly higher in the piglets that were free range combined with tethering or housing (9.6%) compared with the piglets that were fully tethered or housed (7.3%). The study examined the effect of the herd size on the prevalence of RVC, and found that piglets in a herd of 6–10 pigs (10.8%) were more affected. Based on the month of sample collection, there was high prevalence of RVC in July (11.8%) and November (10.5%), however, there was no evidence of seasonal influence on RVC prevalence in the study region, since July is in the dry season and November is in the short rainy season. Nonetheless, we recommend a comprehensive study to elucidate the seasonal influence on RVC prevalence in the study area. The prevalence reported here was lower than the 19.5% reported in the USA [6], 26.3% reported in S. Korea (Jeong et al., 2009), and 28.7% reported in Italy (Martella et al., 2007). However, the previous studies in Korea and Italy analyzed only samples from diarrheic pigs, whereas we used samples from non-diarrheic pigs. The study by Amimo and colleagues in the USA examined fecal samples from both symptomatic and asymptomatic piglets, and reported an overall porcine RVC prevalence of 19.5% with 8.5% in asymptomatic weaned pigs in USA, which is consistent with our results. The study reported high RVC prevalence (23.5%) in younger piglets (
