Livestock Losses Research Articles

Climate Variability and Its Associated Community Losses in Gicumbi District, Northern Rwanda

Climate change causes loss on lives and livelihoods while regular update strengthens resilience. This study aimed to analyze the rainfall variability impact on livelihoods in Northern Rwanda. The data on community losses due to rainfall variability were considered from 2013 to 2019. The GIS and SPSS helped the data analysis process. The results showed high mean monthly rainfall (119.345 and 90.05 mm) in 2013 and 2017, respectively. This caused landslide, flood, rainstorms, windstorms, lightning, and hailstorms occurrence, which killed/injured people, damaged houses and cropland, livestock loss, and destruction of infrastructures. The correlation analysis indicated a statistically significant p-value of 0.0151 lower than 0.05 and approved that rainfall variability negatively impacts livelihoods. This study can enable policymakers to better understand how changes in rainfall impact livelihoods and strategic measures to adopt for climate variability and climate change adaptation.

Use of A MODIS Satellite-Based Aridity Index to Monitor Drought Conditions in Mongolia from 2001 to 2013

The 4D disasters (desertification, drought, dust, and dzud, a Mongolian term for severe winter weather) have recently been increasing in Mongolia, and their impacts on the livelihoods of humans has likewise increased. The combination of drought and dzud has caused the loss of livestock on which nomadic herdsmen depend for their well-being. Understanding the spatiotemporal patterns of drought and predicting drought conditions are important goals of scientific research in Mongolia. This study involved examining the trends of the normalized difference vegetation index (NDVI) and satellite-based aridity index (SbAI) to determine why the land surface of Mongolia has recently (2001–2013) become drier across a range of aridity indices (AIs). The main reasons were that the maximum NDVI (NDVImax) was lower than the NDVImax typically found in other arid regions of the world, and the SbAI throughout the year was large (dry), although the SbAI in summer was comparatively small (wet). Under the current conditions, the capacity of the land surface to retain water throughout the year caused a large SbAI because rainfall in Mongolia is concentrated in the summer, and the conditions of grasslands reflect summer rainfall in addition to grazing pressure. We then proposed a method to monitor the land-surface dryness or drought using only satellite data. The correct identification of drought was higher for the SbAI. Drought is more strongly correlated with soil moisture anomalies, and thus the annual averaged SbAI might be appropriate for monitoring drought during seasons. Degraded land area, defined as annual NDVImax < 0.2 and annual averaged SbAI > 0.025, has decreased. Degraded land area was large in the major drought years of Mongolia.

A Knowledge Based Farm Protection System to Manage Crop Vandalization

Human-Wildlife Conflict (HWC) has direct & indirect negative effects, as crop loss, and livestock loss in India. For crop protection many technical security systems are available thaw they are technologically feasible are not viable financially for the poor land holders working for crop production. Fault removal or maintenance of available techniques are The issues as barrier for the rural people .The proposed work is aimed to reduce the crop vandalization using less complex and cheaper protection system. Solar photovoltaic energy source supported Arduino base circuit is used in this system there for useful for off grid locations too.

Framing of visual content shown on popular social media may affect viewers\u2019 attitudes to threatened species

Content published on social media may affect user’s attitudes toward wildlife species. We evaluated viewers’ responses to videos published on a popular social medium, focusing particularly on how the content was framed (i.e., the way an issue is conveyed to transmit a certain meaning). We analyzed videos posted on YouTube that showed vultures interacting with livestock. The videos were negatively or positively framed, and we evaluated viewers’ opinions of these birds through the comments posted. We also analyzed negatively framed videos of mammalian predators interacting with livestock, to evaluate whether comments on this content were similar to those on vultures. We found that the framing of the information influenced the tone of the comments. Videos showing farmers talking about their livestock losses were more likely to provoke negative comments than videos not including farmer testimonies. The probability of negative comments being posted on videos about vultures was higher than for mammalian predators. Finally, negatively framed videos on vultures had more views over time than positive ones. Our results call for caution in the presentation of wildlife species online, and highlight the need for regulations to prevent the spread of misinformed videos that could magnify existing human-wildlife conflicts.

Assessment of changes over a decade in the patterns of livestock depredation by the Himalayan Brown Bear in Ladakh, India

Conflicts between large carnivores and shepherds constitute a major socio-ecological concern across the Himalaya and affects community attitudes and tolerance toward carnivores. We assessed the extent and intensity of Human-Brown Bear interactions in the same villages of Zanskar and Suru Valleys, Ladakh, in the Indian Trans-Himalaya during two time periods (2001–2003 and 2009–2012) through field and questionnaire surveys. During 2001–2003, 180 families of 32 villages in Zanskar, and 232 families of 49 villages in Suru were interviewed, and during 2009–2012, 145 families of 23 villages in Zanskar and 115 families of 33 villages in Suru were interviewed. Overall, 475 (119/year) and 454 (151/year) heads of livestock were reportedly killed by Brown Bears. The surveys of 2009–2012 revealed that livestock predation in ‘doksas’ (summer grazing camps) was higher (68 %) compared to the surveys carried out during 2001–2003 (42 %). The increased livestock depredation in doksas might be due to the extended stay and use of pastures by the local communities during spring and autumn. Damage to property in the form of breaking open of doors and windows by Brown Bear were reported during both the surveys. Economic losses and declining tolerance of people may trigger retaliatory killings of Brown Bear in Ladakh. We recommend compensation for livestock loss and improved husbandry practices in the conflict zones for bear-human coexistence.

Every case is different: Cautionary insights about generalisations in human-wildlife conflict from a range-wide study of people and jaguars

Throughout their range, jaguars (Panthera onca) are persecuted for killing livestock, posing a widespread and serious threat to their survival. Human-jaguar conflict occurs across a very large variety of geographic, agronomic and socio-economic contexts and across heterogeneous communities. We conducted seventeen case studies across seven countries in central and south America to search for patterns in socio-economic predictors of human-jaguar conflict that could help up-scale management of this range-wide jaguar conservation challenge. Our study revealed that within and across case studies there were considerable differences in farmers' education levels, economic dependence on livestock, personal experience with livestock losses, as well as tolerance of and attitudes and social norms towards jaguars. Among this diversity, we sought common predictors of tolerance of jaguars, but found that no quantifiable single contextual factor could be used to predict how farmers perceive jaguars and deal with depredation. While patterns did exist within individual case studies, none of these were consistent across a majority of cases. We conclude that observations of patterns in human-wildlife conflict are valid only for informing action at a local scale, and even if a small number of case studies appear to show similar patterns this does not make the observation universally true. It is important to remember not to generalise from case studies. Nevertheless, although each case is likely to require individual solutions, insights from aggregate or wide-range studies can provide insights into the range of possible scenarios, adding breadth of information to depth of local knowledge.

Veterinary Phytomedicine in India : A Review

Nature is a unique source of structures of high phytochemical diversity, many of them possessing interesting biological activities and medicinal properties. Phytochemicals ensure safe, eco-friendly and most effective drug for animal use. Veterinarians use these phytochemicals with the knowledge from traditional system and modern pharmacology. High cost of allopathic medicine is one of the major contributing factors in loss of productive livestock and animal productivity. Many plants have been identified which show promising abilities in disease prevention and cure. Phytochemicals can be used either by feeding whole plant parts or by the process of extraction of these chemicals and delivering in concentrated forms. The pharmacological activities of plants are attributed to certain active principles, namely alkaloids, glycosides, fats, oils, tannins, saponins etc. The use of cheap and easily available phytochemicals can thus be made by taking a leaf out of the ethno-veterinary practices. Although the effects of natural remedies may seem slower, the results are sometimes better on the long run especially with respect to chronic diseases. The horizon of phytochemicals has to be explored and exploited to create a “green treatment” protocol to develop an ecofriendly and toxin free production system that is beneficial for existence of both human and animal population in the near future.

Attitudes Towards a Transient Carnivore Prior to Recolonization

ABSTRACTCougars (Puma concolor) have been recolonizing portions of their historic range over the last few decades and are currently a rare, transient species in the western Great Lakes Region. Anticipatory attitude surveys can identify potential management challenges, stakeholder groups, and conservation and educational priorities for recolonizing cougars. We implemented an anticipatory attitude survey to better understand attitudes towards transient cougars in northern Wisconsin, USA. We distributed the survey in fall and early winter of 2014–15 (n = 423) and 2015–16 (n = 594). We compared attitudes towards transient cougars to attitudes towards other established large carnivores and white‐tailed deer (Odocoileus virginianus). We also explored factors that may affect human attitudes towards cougars, such as hunter identity, livestock ownership, risk perception, and the loss of a domestic animal to wildlife. Despite the rare, transient status of cougars in Wisconsin, many respondents (mean of 29%) reported to have observed a cougar or sign of one in the wild in Wisconsin. Cougars had a mean favorability score similar to coyotes (Canis latrans) and wolves (Canis lupus) and less than bobcats (Lynx rufus), bear (Ursus americanus), and white‐tailed deer. Comparatively, respondents’ risk perception for all categories of risk (i.e., fear for personal safety, the safety of children, and the safety of domestic animals) was higher for cougars than for wolves. Hunter identity and loss of livestock to wildlife were determined by multinomial logistic regression as the most important parameters affecting respondents’ favorability towards cougars (ωi = 0.71). Using the 2015–2016 survey data, we found that as cougar risk perception increased, favorability towards cougars decreased similarly for both hunters and non‐hunters. Hunters were less likely to be favorable towards cougars, more likely to be neutral, and equally likely to be unfavorable towards cougars compared to nonhunters. We identify potential management challenges, stakeholder groups (e.g., hunters and those who have experienced loss of livestock to wildlife), and conservation and educational priorities for recolonizing cougars. © 2021 The Wildlife Society.

Leptospirosis in Ruminants in Yogyakarta, Indonesia: A Serological Survey with Mixed Methods to Identify Risk Factors

Leptospirosis is a zoonotic disease occurring worldwide with reproductive symptoms and production losses in livestock, while humans can suffer fatal renal failure. In Yogyakarta Special Province, Indonesia, there have been several outbreaks with high case fatality, demonstrating the public health importance, but there is limited understanding of the epidemiology. This study used an EcoHealth approach to ensure transdisciplinarity and community participation. Seroprevalence of Leptospira in animals was studied between October 2011 and May 2013 in 15 villages. Serum samples from 1404 cattle and 60 small ruminants were screened by a Microscopic Agglutination Test (MAT), first in pools, and then the individual positive samples were identified. Focus group discussions including farmers, village officials, and official stakeholders were used to explore knowledge and behavior of zoonotic diseases, particularly leptospirosis. Two small ruminants were seropositive for Leptospira icterohemorrhagiae. From the cattle, 3.7% were seropositive, and the most common serovars were Leptospira hardjo, followed by L. icterohemorrhagiae. Out of all farms, 5.6% had at least one positive cattle. Risk factor analyses showed that the risk of the farm being seropositive increased if the farmer used water from an open source, or if farming was not the main occupation. This study showed the presence of Leptospira spp. in ruminants in Yogyakarta and identified use of open water as a risk factor for the livestock. We also observed that the knowledge related to leptospirosis was low, and risky farm management practices were commonly employed.

Farmer perceptions of carnivores, their culpability for livestock losses, and the protective measures used in Northern Cape Province, South Africa

Livestock losses are often integral to human conflicts over carnivores; these conflicts threaten the livelihoods of many communities, as well as carnivore species survival. To begin assessing livestock depredation and conflict over carnivores in South Africa's Northern Cape Province, a farmers' union meeting was used to capture farmer (n = 22) perceptions of carnivores in 2017. Most farmers reported black-backed jackals and caracals (n = 11 and 10, respectively) as most frequently culpable for livestock losses. However, culpability and reported presence on farmlands by these and other carnivore species were not always aligned. Carnivores were generally perceived in a negative manner, with most respondents supporting livestock protection methods involving the removal or separation of carnivores from farmland, as opposed to those facilitating coexistence. Comprehensive socio-ecological investigation of factors relevant to improving human-carnivore coexistence of benefit to both farmers and wildlife is warranted in this region.

Predator tourism improves tolerance for pumas, but may increase future conflict among ranchers in Chile

Predator tourism is one strategy to improve tolerance for predators, and support biodiversity and ecosystem health. Torres del Paine National Park (TdP) – a UNESCO Biosphere Reserve in southern Chile - supports productive livestock industries and nascent puma tourism. We compared interviews conducted in the region prior to puma tourism, with results from interviews collected across 45 ranches post-puma tourism. We assessed rancher attitudes regarding pumas, puma-livestock conflict, puma tourism, and linked them with socio-ecological factors. Respondents who viewed pumas as a threat experienced higher livestock losses. Respondents who reported higher sheep losses were inclined to support the lethal removal of livestock-killing pumas, and to initiate a puma hunt, whereas respondents who supported puma tourism disagreed with hunting pumas. Using the Potential for Conflict Index, we found that participants exhibited the highest consensus on the benefit of puma tourism and the lowest consensus over lethal removal of pumas. Our results suggest predator tourism has increased tolerance for pumas but is creating new potential for conflict. Previous to puma tourism, ranchers were almost entirely negative about pumas and unanimously supported illegal puma hunting. Now, most believe that pumas are part of Patagonia's heritage. This divide was best explained by distance to TdP: ranches closer to TdP experienced greater losses to pumas but had neighbours that benefitted most from puma tourism. Therefore, we suggest that tourism revenues supplement community compensation insurance programs that reimburse rancher losses to pumas to mitigate the growing divide between those benefiting from pumas and those experiencing economic hardship.

Analysis of residential satisfaction: An empirical evidence from neighbouring communities of Rohingya camps in Cox's Bazar, Bangladesh.

This study aims to understand the level of residential satisfaction of the host communities' aftermath of the influx of Rohingya in Bangladesh. A total of 151 household heads were randomly interviewed from Ukhiya and Ramu Upazila of Cox's Bazar district, Bangladesh. A residential satisfaction index is developed with a total of twenty-two variables comprised of four components- social environment (SE), neighbourhood environment (NE), public services and facilities (PS&F), and dwelling units (DU). The coefficients of the components indicate that the PS&F, SE, and NE impact much on the overall residential satisfaction compare to the DU. The analysis demonstrates that the people who have tertiary level education, who is Muslim and whose work opportunities remain the same as before, are more satisfied, but older people are less satisfied than younger. Besides, the degradation of social harmony, livestock and agricultural land losses, and decreased wages were the significant causes of dissatisfaction. These findings may contribute to taking appropriate policies and programs for the host communities taken by the government and non-government organizations.

Patterns of rabies cases in South Africa between 1993 and 2019, including the role of wildlife.

Rabies is a global viral zoonosis endemic to South Africa, resulting in fatal encephalitis in warm-blooded animals, including humans. The loss of human lives and economic losses in rural areas through loss of livestock are substantial. A review was conducted of all confirmed animal rabies cases in South Africa from 1993 to 2019, with a total of 11701 cases identified to species level to assess the role that wildlife plays in the epidemiology of rabies. A spatio-temporal cluster analysis using a discrete Poisson space-time probability model, accounting for underlying estimated dog and livestock densities, identified 13 significant clusters (p<.05). These included four long-term clusters lasting more than 8years in duration and seven short-term clusters lasting less than 2years, with the remaining two clusters being of intermediate length. Outside of these endemic clusters, wildlife outbreaks in the remainder of South Africa were often less than one and a half years in duration most likely due to the rapid decline of wildlife vectors, especially jackals associated with rabies infection. Domestic dogs accounted for 59.8% of cases, with domestic cats (3.2%), livestock (21.1%) and wildlife (15.8%) making up the remainder of the cases. Yellow mongoose (Cynictis penicillata) was the most frequently affected wildlife species, followed by bat-eared fox (Otocyon megalotis), black-backed jackal (Canis mesomelas), meerkat (Suricata suricatta) and aardwolf (Proteles cristatus). Rabies in wildlife species followed different spatial distributions: black-backed jackal cases were more common in the north-western parts of South Africa, yellow mongoose cases more frequent in central South Africa, and bat-eared fox and aardwolf cases were more frequent in southern and western South Africa. Clusters often spanned several provinces, showing the importance of coordinated rabies control campaigns across administrative boundaries, and high-risk areas were highlighted for rabies in South Africa.

Vaccination against pathogenic clostridia in animals: a review.

Clostridium is a Gram-positive, rod-shaped, anaerobic, and spore-forming bacterium, which is found in the surrounding environments throughout the world. Clostridium species cause botulism, tetanus, enterotoxaemia, gas gangrene, necrotic enteritis, pseudomembranous colitis, blackleg, and black disease. Clostridium infection causes severe economic losses in livestock and poultry industries. Vaccination seems to be an effective way to control Clostridial diseases. This review discusses the toxins and vaccine development of the most common pathogenic Clostridium species in animals, including Clostridium perfringens, Clostridium novyi, Clostridium chauvoei, and Clostridium septicum. In this comprehensive study, we will review different kinds of clostridial toxins and the vaccines that are experimentally or practically available and will give a short description on each vaccine focusing on its applications, advantages, and disadvantages.

Salmonella Enteritidis foodborne infection induces altered placental morphometrics in the murine model

IntroductionSalmonella foodborne disease during pregnancy causes a significant fetal loss in domestic livestock and preterm birth, chorioamnionitis and miscarriage in humans. These complications could be associated with alterations in placental structure. This study was aimed to determine how a low dose of Salmonella Enteritidis during late gestation affects placental histomorphometric in mice. MethodsWe used a self-limiting enterocolitis murine model. BALB/c pregnant animals received a low dose of Salmonella Enteritidis (3–4 x 102 CFU/mouse) on gestational day (GD) 15. At day 3 post infection bacterial loads, serum cytokines expression and placental histomorphometrics parameters were analyzed. ResultsWe found that a sub-lethal infection with Salmonella induced a significant drop in fetal weight -to-placental weight-ratio and an increase in the placental coefficient. After bacterial inoculation maternal organs were colonized, inducing placental morphometric alterations, including increased placental thickness, reduced surface area, and diminished major and minor diameters. Also, foci of necrosis accompanied by acute leukocyte infiltration in decidual zone, reduction of vascular spaces and vascular congestion in labyrinth zone, were also evident in placentas from infected females on GD 18. Our data shows that placentas from infected mothers are phenotypically different from control ones. Furthermore, expression of IFN-gamma and IL-6 was up regulated in response to Salmonella in maternal serum. DiscussionOur findings demonstrate that a low dose of Salmonella during late gestation alters the placental morphometry leading to negative consequences on pregnancy outcome such as significant reduction in fetal body weight.

Assessing the Effectiveness of a Community-based Livestock Insurance Program.

Financial mechanisms to mitigate the costs of negative human-carnivore interactions are frequently promoted to support human coexistence with carnivores. Yet, evidence to support their performance in different settings is scarce. We evaluated a community-based livestock insurance program implemented as part of a broader snow leopard conservation effort in the Tost Tosonbumba Nature Reserve, South Gobi, Mongolia. We assessed program efficiency and effectiveness for snow leopard conservation using a results-based evaluation approach. Data sources included program records from 2009 to 2018, as well as surveys conducted in 2016 and 2017, which allowed us to compare key indicators across communities that participated in the insurance program and control communities. Program coverage and number of livestock insured rapidly increased over the years to reach 65% of households and close to 11,000 livestock. Participants expressed satisfaction with the program and their contributions increased over time, with an increasing proportion (reaching 64% in 2018) originating from participant premiums, suggesting strong community ownership of the program. Participants were less likely to report the intention to kill a snow leopard and reported fewer livestock losses than respondents from control communities, suggesting increased engagement in conservation efforts. These results together suggest that the insurance program achieved its expected objectives, although it is challenging to disentangle the contributions of each individual conservation intervention implemented in intervention communities. However, in the first three years of the program, snow leopard mortalities continued to be reported suggesting that additional interventions were needed to reach impact in terms of reducing retaliatory killings of large carnivores.

Ecological determinants of livestock depredation by the snow leopard Panthera uncia in Bhutan

AbstractRetaliatory killing due to livestock depredation is a major threat to snow leopard (Panthera uncia) conservation. To devise management actions that reduce livestock losses and the consequent retaliatory killing, we need to understand the factors that influence the snow leopard's diet and depredation on livestock. Here, we studied snow leopard diet and ecological determinants of livestock depredation in Bhutan by semi‐systematically collecting scat samples and analysing prey hair structure using a micro‐histological method. We identified five prey species. Most of the snow leopard diet consisted of wild ungulates (85.8%), mostly bharal (60.8%). Yak (14.2%) was the only livestock species in the scats. Livestock depredation was higher during summer and differed markedly among four protected areas characterized by various wildlife densities and human activities. These findings will help develop a site‐based management plan to ensure the long‐term persistence of the snow leopard in Bhutan.

Sero-diagnostic studies on the occurrence and prevalence of bovine spongiform encephalopathies in Nasarawa state, Nigeria

The study was conducted to determine the occurrence and the prevalence of bovine spongiform encephalopathy among cattle herds in Nasarawa State, Nigeria using targeted sampling approach. The procedure of sampling adapted was a “double” targeted method for survey. First, a BSE risk group was targeted ‘emergency or casualty slaughter’ and within this Group, animals with signs indicative for BSE were sub-targeted. Two sampling locations were chosen; Akwanga central abattoir and Lafia central abattoir, both located in Nasarawa North and Nasarawa south senatorial district. Immediately the suspected animals were slaughtered, the caudal brain stem was harvested and examined for the disease specific form of the prion protein, PrPSc, using Western Blot technique after proteinase K digestion. A total of 2000 cattle of local breeds, aged ≥ 24 months and above were clinically examined. A total of 147 (7.4 %) of the cattle sampled were clinically suspicious for BSE. No sample was positive for BSE. Fluorescent antibody test for rabies and H&amp;E staining on samples were carried out to observe for differential diagnosis. These showed no pathological lesions indicative for neurological disease. While our findings do not exclude the presence of BSE in Nasarawa State, we demonstrate that targeted sampling of ruminants for neuroinfectious disease is possible in developing countries, pointing to the possibility of implementing such a monitoring scheme in Nigeria to prevent economic losses in ruminant livestock as BSE caveats from endemic countries have shown.

Beauty or beast? Farmers' dualistic views and the influence of aesthetic appreciation on tolerance towards black-backed jackal and caracal.

Various species of wild, adaptable, medium-sized carnivores occur outside of protected areas, often coming into contact with people and their domestic animals. Negative human-carnivore interactions can lead to antagonistic attitudes and behavior directed at such species. In the South African Karoo, a semi-arid rangeland, the predation of small-livestock by mesopredators is common and farmers typically use a combination of non-lethal and lethal methods to try and prevent livestock losses. We used ethnographic field observations and semi-structured interviews as part of a mixed methods approach, including the quantitative and qualitative analysis of farmers’ narratives to illustrate the nuanced ways in which sheep farmers relate to the two mesopredators that consume the most livestock on their farms; black-backed jackal and caracal. Overall, farmers attributed negative characteristics to jackal and caracal but farmers’ narratives provided evidence of complex perceptions in that the animals were admired as well as disliked. Both species were seen as charismatic due to traits such as their physical appearance, their “cunning” nature and their remarkable adaptability to human activities, including lethal control. Aesthetic appreciation was an important predictor of tolerance towards both species whereas negative attitudes were associated with the perception that mesopredators should only occur within protected areas. Attitudes towards jackals also appeared to have been affected by cultural representations of them as “thieves”. We showed that perceiving mesopredators as beautiful increased the average marginal probability of a farmer tolerating them, and that this strong relationship held when controlling for other covariates such as livestock predation. We advocate the importance of understanding the cultural and aesthetic aspects of predators and considering existing positive dimensions of human-wildlife relationships that may encourage increased farmers’ tolerance, which might promote coexistence.

Two novel loci underlie natural differences in Caenorhabditis elegans abamectin responses.

Parasitic nematodes cause a massive worldwide burden on human health along with a loss of livestock and agriculture productivity. Anthelmintics have been widely successful in treating parasitic nematodes. However, resistance is increasing, and little is known about the molecular and genetic causes of resistance for most of these drugs. The free-living roundworm Caenorhabditis elegans provides a tractable model to identify genes that underlie resistance. Unlike parasitic nematodes, C. elegans is easy to maintain in the laboratory, has a complete and well annotated genome, and has many genetic tools. Using a combination of wild isolates and a panel of recombinant inbred lines constructed from crosses of two genetically and phenotypically divergent strains, we identified three genomic regions on chromosome V that underlie natural differences in response to the macrocyclic lactone (ML) abamectin. One locus was identified previously and encodes an alpha subunit of a glutamate-gated chloride channel (glc-1). Here, we validate and narrow two novel loci using near-isogenic lines. Additionally, we generate a list of prioritized candidate genes identified in C. elegans and in the parasite Haemonchus contortus by comparison of ML resistance loci. These genes could represent previously unidentified resistance genes shared across nematode species and should be evaluated in the future. Our work highlights the advantages of using C. elegans as a model to better understand ML resistance in parasitic nematodes.