The endoparasitism challenge in developing countries as goat raising develops from smallholder to commercial production systems: A study from Laos

Windsor, Peter; Nampanya, S.; Putthana, V.; Keonam, K.; Johnson, Kris; Bush, R. D.; Khounsy, Syseng

doi:10.1016/j.vetpar.2017.12.025

Cited by 19 publications

(27 citation statements)

References 11 publications

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“…In previous studies regarding GINs from Sudan using postmortem worm recovery, the two latter genera were also not reported in sheep and goats [64,65]. As expected and in agreement with previous results obtained by morphological differentiation of L3 [66,67], H. contortus was detected in 100% of L3 samples collected after albendazole treatment in the four study areas, no matter if goats were treated with 5 mg/kg or if the dose was increased up to 12.5 mg/kg bw. In contrast to previous reports using larval cultures and morphological differentiation, in the present study, based on molecular identification Trichostrongylus spp.…”

Section: Taasupporting

confidence: 92%

New codon 198 β-tubulin polymorphisms in highly benzimidazole resistant Haemonchus contortus from goats in three different states in Sudan

et al. 2020

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Background: Benzimidazole (BZ) resistance in gastrointestinal nematodes is a worldwide problem for livestock production, particularly in small ruminants. Assignment of the emergence of resistance using sensitive and reliable methods is required to adopt the correct strategies for control. In Sudan, BZ resistant Haemonchus contortus populations were recently reported in goats in South Darfur. This study aimed to provide additional data regarding albendazole efficacy and to describe the prevailing molecular BZ resistance mechanisms. Methods: Faecal egg count reduction and egg hatch tests (EHT) were used to evaluate albendazole efficacy in three different areas of South Darfur using naturally (Rehed Al-Birdi and Tulus) and experimentally infected (Tulus and Um Dafuq) goats. Using samples from Central, East and South Darfur, pyro-and Sanger sequencing were used to detect the polymorphisms F167Y, E198A and F200Y in H. contortus isotype 1 β-tubulin in DNA extracted from pooled thirdstage larval (L3) samples (n = 36) on days 0 and 10 during trials, and from pooled adult male H. contortus (treated goats, n = 14; abattoirs, n = 83) including samples from populations previously found to be resistant in South Darfur. Results: Albendazole efficacies at 5, 7.5 and 10 mg/kg doses were 73.5-90.2% on day 14 in natural and experimental infections while 12.5 mg/kg showed > 96.6% efficacy. EC 50 in the EHT were 0.8 and 0.11 µg/ml thiabendazole in natural and experimental infection trials, respectively. PCRs detected Haemonchus, Trichostrongylus and Cooperia in L3 samples from albendazole-treated goats. Haemonchus contortus allele frequencies in codons 167 and 200 using pyrosequencing assays were ≤ 7.4% while codon 198 assays failed. Sanger sequencing revealed five novel polymorphisms at codon 198. Noteworthy, an E198L substitution was present in 82% of the samples (L3 and adults) including all post-treatment samples. Moreover, E198V, E198K and potentially E198I, and E198Stop were identified in a few samples. Conclusions: To our knowledge, this is the first report of E198L in BZ resistant H. contortus and the second where this is the predominant genotype associated with resistance in any strongyle species. Since this variant cannot be quantified using pyrosequencing, the results highlight important limitations in the general applicability of pyrosequencing to quantify BZ resistance genotypes.

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Section: Taasupporting

confidence: 92%

New codon 198 β-tubulin polymorphisms in highly benzimidazole resistant Haemonchus contortus from goats in three different states in Sudan

et al. 2020

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“…In an endemic country, the serological results would very likely be clustered. It remains possible that there has been outbreak of PPR in Laos without detection or declaration due to suboptimal veterinary capacity in some areas (Bastiaensen et al., ), or that PPR may have been mistaken for other diseases, such as FMD and endoparasites; both are endemic in Laos (Nampanya et al., ; Windsor et al., ). However, it is also possible, although unlikely, that subclinical disease or mild infections could be responsible for an anti‐PPR antibody response without clinical signs (Balamurugan, Das et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…However, the occurrence of similar endemic diseases and poor veterinary infrastructure may lead to PPR being missed or underdiagnosed. Differential diagnoses for PPR in Laos may include foot and mouth disease virus (FMD) (Nampanya et al., ), ovine parapoxvirus induced Contagious Ecthyma (Windsor et al., ), Coxiellosis (Burns et al., ), Brucellosis (Burns et al., ) and intestinal parasites (Windsor et al., ). Laos is considered as being “at risk” of PPRV incursion due to: proximity and trade with PPR‐endemic China; it is a landlocked country with “porous” borders enabling livestock trade between ASEAN countries; and the relatively poor veterinary infrastructure with suboptimal capacity to detect and respond to emergency and/or emerging disease outbreaks (Bastiaensen, Kamakawa, & Varas, ; Nampanya et al., ).…”

Section: Introductionmentioning

confidence: 99%

Peste des Petits Ruminants ( PPR ) virus serological surveillance in goats in Lao PDR : Issues for disease eradication in a low‐resource disease‐free setting

Burns

Douangngeun

Theppangna

et al. 2019

Transbound Emerg Dis

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Peste des Petits ruminants (PPR) is an economically important transboundary viral disease of goats. This study aimed to determine a baseline of serological evidence for Peste des petits ruminants virus (PPRV) in Lao goats. A total of 1,072 serum samples were collected by convenience sampling across five provinces in Laos and tested for antibody response to PPRV using a commercially available competitive ELISA. Positive antibody responses were found in 2.2% (95% CI 1.4, 3.2) of the samples. True prevalence calculations indicated a total overall sample prevalence of 1.7% (95% CI 0.9, 2.8). The highest provincial seroprevalences were Xiangkhouang (3.5%, 95% CI 1.6, 6.9) and Xayaboury (2.9% (95% CI 1.3, 5.7). There was no association between antibody response and each of the following factors: location, breed, gender or age. Considering the apparent absence of disease manifestation of PPR in Laos, likely explanations for the antibody positivity could include cross reaction to other Morbilliviruses such as Measles or Canine Distemper, importation of pre‐vaccinated goats, need for test cut‐off re‐evaluation to be region specific, or a subclinical and a less virulent circulating virus. This study highlights that the sampled Lao goat population is highly likely to be naïve to PPRV and therefore at risk of an outbreak, possibly by transboundary incursion of livestock from PPR endemic China. Further work is required in the testing of small ruminants in Laos that may eventually provide evidence for a status of freedom from disease, particularly in support of programs aimed at global PPR eradication.

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“…The world goat population continues to increase, exceeding one billion globally, with 90% of goats raised in Asia and Africa (Monteiro et al, 2018;Hegde, 2020) and particularly in the rural and remote areas of developing countries (Skapetas & Bampidis, 2016). In the Lao People's Democratic Republic (Laos), goat production has doubled since 2011 (Windsor et al, 2018;Burns et al, 2019) and has progressively increased over consecutive years, with total numbers of 560,000, 588, 000, 616,325, and 639,715 head in 2016, 2017, 2018, and 2019, respectively (http://www.fao.org/faostat/en/#data/QA). However, goats in Laos are not only a source of high protein food and cash income for poor families within the country, but the goat meat is also exported to neighboring countries such as Vietnam, and China (Burns et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Goat production in Laos must now deal with many factors including diseases caused by internal parasites (Wilson, 2007;Windsor et al, 2018). Haemonchus spp.…”

Section: Introductionmentioning

confidence: 99%

Cuticular ridge patterns applied for identifying adult female worms of Haemonchus species with various vulvar morphological types in infected native goats in Laos

2021

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Species of the blood sucking nematode Haemonchus are a main problem in the small ruminant industry worldwide. Haemonchus worms were taken from 68 infected native goats slaughtered in three provinces of Laos in June and July 2019. Cuticular ridge patterns were used for the first time to identify adult female Haemonchus spp. and their vulvar morphs were characterized. The results showed that the variations in vulvar morphology of female Haemonchus spp. presented a knobbed morph as the dominant morphotype and predominant linguiform B subtype was also detected. In total, 270 selected female worms from each vulvar morph type were examined based on their cuticular ridge patterns in cross sections at positions of the esophageal-intestinal junction (EI), the 4 mm region from the anterior end (4 mm), and the mid-body (MB). Only Haemonchus contortus was identified and most worms had constant numbers of ridges at EI, 4 mm, and MB, namely 30, 26, and 22 ridges, respectively, accounting for 99.26%, 97.41%, and 97.04%, respectively, of worms detected, while the lowest variation in the number of ridges was at region EI which is recommended as the single best position. Based on synlophe and ITS2 sequence analysis, it was assumed that H. contortus might dominate in the sample areas with the possible numbers of ridges of H. contortus females in the ranges 29-30, 25-27, and 21-23 for positions EI, 4 mm, and MB, respectively. The cuticular ridge pattern was a useful character for identifying female Haemonchus species in this study and could be utilized as an affordable alternative method for epidemiological studies and as part of parasite control management in native goats of Laos.

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The endoparasitism challenge in developing countries as goat raising develops from smallholder to commercial production systems: A study from Laos

Cited by 19 publications

References 11 publications

New codon 198 β-tubulin polymorphisms in highly benzimidazole resistant Haemonchus contortus from goats in three different states in Sudan

New codon 198 β-tubulin polymorphisms in highly benzimidazole resistant Haemonchus contortus from goats in three different states in Sudan

Peste des Petits Ruminants ( PPR ) virus serological surveillance in goats in Lao PDR : Issues for disease eradication in a low‐resource disease‐free setting

Cuticular ridge patterns applied for identifying adult female worms of Haemonchus species with various vulvar morphological types in infected native goats in Laos

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