Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.

Smallholder large ruminant production in Lao People's Democratic Republic (Laos) is characterised by low reproductive efficiency. To determine if common abortifacient bovid infectious diseases are involved, a serological investigation was conducted. Sera was collected from stored and fresh catt...

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Main Authors: Luisa Olmo, Michael P Reichel, Sonevilay Nampanya, Syseng Khounsy, Lloyd C Wahl, Bethanie A Clark, Peter C Thomson, Peter A Windsor, Russell D Bush
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2019-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0220335
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author Luisa Olmo
Michael P Reichel
Sonevilay Nampanya
Syseng Khounsy
Lloyd C Wahl
Bethanie A Clark
Peter C Thomson
Peter A Windsor
Russell D Bush
author_facet Luisa Olmo
Michael P Reichel
Sonevilay Nampanya
Syseng Khounsy
Lloyd C Wahl
Bethanie A Clark
Peter C Thomson
Peter A Windsor
Russell D Bush
author_sort Luisa Olmo
collection DOAJ
description Smallholder large ruminant production in Lao People's Democratic Republic (Laos) is characterised by low reproductive efficiency. To determine if common abortifacient bovid infectious diseases are involved, a serological investigation was conducted. Sera was collected from stored and fresh cattle (n = 390) and buffalo (n = 130) samples from 2016-18 from, and then examined for associations in a retrospective risk factor study of 71 herds. The sera were assayed for antibodies to Neospora caninum, bovine viral diarrhoea virus (BVDV), Leptospira interrogans serovar Hardjo and Brucella abortus using commercially available enzyme-linked immunosorbent assay kits. These pathogens were detected in buffalo samples at 78.5% (95% CI 71.4-85.6), 0%, 2.3% (95% CI 0-4.9) and 0%, respectively, and in cattle at 4.4% (95% CI 2.4-6.4), 7.7% (95% CI 3.1-12.3), 12.8% (95% CI 9.5-16.1) and 0.26% (95% CI 0-0.8), respectively. Exposure of buffalo to N. caninum was positively associated with buffalo age, with a predicted seropositivity at birth of 52.8%, increasing to 97.2% by 12 years of age (p = 0.037). Exposure of cattle to L. interrogans serovar Hardjo was more prevalent in females compared to males, was associated with higher titres of BVDV, and was more prevalent in the wet season compared to the dry season. Exposure of cattle to BVDV was more prevalent in males compared to females, the wet and dry seasons were comparable, and was associated with rising antibody titres against N. caninum and L. interrogans serovar Hardjo. The risk factor survey identified that the probability of herds being N. caninum positive increased with farmer age, if farmers believed there were rodents on farm, and if farmers weren't aware that canids or rodents could contaminate bovid feed on their farm. The probability of a herd being positive to L. interrogans serovar Hardjo increased on farms where multiple cows shared the same bull, where farmers had lower husbandry knowledge, and on farms that used water troughs. The probability of a herd being BVDV seropositive increased with increasing herd size and increasing titres to N. caninum. The benchmarking of bovid exposure to emerging abortifacient pathogens and identification of their risk factors potentially informs disease prevention strategies, supporting efforts to establish a biosecure beef supply for enhanced smallholder livestock productivity, public health and food security in Laos and surrounding countries.
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spelling doaj.art-abf2a9730dbd405786f10c7306c47c812022-12-21T23:11:23ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-01148e022033510.1371/journal.pone.0220335Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.Luisa OlmoMichael P ReichelSonevilay NampanyaSyseng KhounsyLloyd C WahlBethanie A ClarkPeter C ThomsonPeter A WindsorRussell D BushSmallholder large ruminant production in Lao People's Democratic Republic (Laos) is characterised by low reproductive efficiency. To determine if common abortifacient bovid infectious diseases are involved, a serological investigation was conducted. Sera was collected from stored and fresh cattle (n = 390) and buffalo (n = 130) samples from 2016-18 from, and then examined for associations in a retrospective risk factor study of 71 herds. The sera were assayed for antibodies to Neospora caninum, bovine viral diarrhoea virus (BVDV), Leptospira interrogans serovar Hardjo and Brucella abortus using commercially available enzyme-linked immunosorbent assay kits. These pathogens were detected in buffalo samples at 78.5% (95% CI 71.4-85.6), 0%, 2.3% (95% CI 0-4.9) and 0%, respectively, and in cattle at 4.4% (95% CI 2.4-6.4), 7.7% (95% CI 3.1-12.3), 12.8% (95% CI 9.5-16.1) and 0.26% (95% CI 0-0.8), respectively. Exposure of buffalo to N. caninum was positively associated with buffalo age, with a predicted seropositivity at birth of 52.8%, increasing to 97.2% by 12 years of age (p = 0.037). Exposure of cattle to L. interrogans serovar Hardjo was more prevalent in females compared to males, was associated with higher titres of BVDV, and was more prevalent in the wet season compared to the dry season. Exposure of cattle to BVDV was more prevalent in males compared to females, the wet and dry seasons were comparable, and was associated with rising antibody titres against N. caninum and L. interrogans serovar Hardjo. The risk factor survey identified that the probability of herds being N. caninum positive increased with farmer age, if farmers believed there were rodents on farm, and if farmers weren't aware that canids or rodents could contaminate bovid feed on their farm. The probability of a herd being positive to L. interrogans serovar Hardjo increased on farms where multiple cows shared the same bull, where farmers had lower husbandry knowledge, and on farms that used water troughs. The probability of a herd being BVDV seropositive increased with increasing herd size and increasing titres to N. caninum. The benchmarking of bovid exposure to emerging abortifacient pathogens and identification of their risk factors potentially informs disease prevention strategies, supporting efforts to establish a biosecure beef supply for enhanced smallholder livestock productivity, public health and food security in Laos and surrounding countries.https://doi.org/10.1371/journal.pone.0220335
spellingShingle Luisa Olmo
Michael P Reichel
Sonevilay Nampanya
Syseng Khounsy
Lloyd C Wahl
Bethanie A Clark
Peter C Thomson
Peter A Windsor
Russell D Bush
Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
PLoS ONE
title Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
title_full Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
title_fullStr Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
title_full_unstemmed Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
title_short Risk factors for Neospora caninum, bovine viral diarrhoea virus, and Leptospira interrogans serovar Hardjo infection in smallholder cattle and buffalo in Lao PDR.
title_sort risk factors for neospora caninum bovine viral diarrhoea virus and leptospira interrogans serovar hardjo infection in smallholder cattle and buffalo in lao pdr
url https://doi.org/10.1371/journal.pone.0220335
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