Prevalence Of Nematodes Research Articles

Epidemiology of Gastrointestinal Nematodes in Small Ruminants in Gamo Zone, Southern Ethiopia, with a Special Reference to Field Survey on Parasite Management and Risk Factor Analysis

Gastrointestinal nematodes are a major constraint for small ruminant production. A cross-sectional study was conducted in the districts of Gamo Zone, Southern Ethiopia on 415 small ruminants (248 sheep and 167 goats) selected using simple random sampling technique from this region to investigate the epidemiology of gastrointestinal nematodes (GINs) and potential risk factors. Coprological examination using floatation, McMaster egg counting and larviculture were employed. The overall prevalence of gastrointestinal nematode was 68.92%. Different nematode types including strongyles (54.94%), Strongyloides papillosus. (2.65%) and Trichuris sp. (1.93%) were identified based on egg morphology with overall mean faecal egg count of 307.66 ± 38.02. Haemonchus, Trichostrongylus, Oesophagostomum, Bunostomum, Cooperia, Teladorsagia and Chabertia were identified from pooled culture. The study revealed female animals were 1.99 times (OR=1.99, 95%CI=1.16-3.41) more likely to be affected by GIN infection than males. Animals with poor (OR=2.92, 95%CI=1.32-6.45) and medium (OR=1.94, 95%CI=1.13-3.34) body condition were 2.92 and 1.94 times more likely to be affected by GINs than those with good body condition. Pregnant animals were 6.57 times (OR=6.57, 95%CI=1.49-28.89) more likely to have GINs than non-pregnant animals. Infection in young animals was 1.8 times higher (OR=1.8, 95%CI=1.05-4.2) than adults. Appropriate prevention and control methods have to be undertaken to overcome the existing problem and further study is needed to assess seasonal dynamics of the GINs.

Prevalence of endoparasites by microscopic analysis in free-range chickens in a Brazilian semiarid region.

The aim of this study was to evaluate the prevalence and diversity of endoparasitic fauna and the risk factors associated with parasite infections in free-range chickens in the state of Paraíba, northeastern Brazil. Ten municipalities were visited and, in each of them, ten farms, to collect animal feces and apply epidemiological questionnaires. Feces from 417 poultry were used to perform EPG (eggs per gram) and OoPG (oocysts per gram) tests. Prevalences of 40.52% (169/417) and 39.08% (163/417) were observed for nematodes and coccidia, respectively. In 17% (71/417), mixed infections by nematodes and coccidia were observed. Nematodes of Heterakoidea superfamily were present in 100% of the positive samples (169/169), followed by Trichuris spp. (57.3%; 97/169). All the protozoan oocysts observed belonged to the genus Eimeria (100%; 163/163). The variable of presence of drooping wings was considered to be a factor associated with infection by coccidia (odds ratio = 5.412; confidence interval: 1.179-24.848; p = 0.030). It was concluded that there is high prevalence of nematodes and coccidia in free-range chickens in the state of Paraíba, Brazil. Better sanitary management measures, with greater hygiene of facilities, together with chemical control of parasites, can improve productivity by reducing the rate of gastrointestinal parasites.

Prevalence and Molecular Diversity of Plant-Parasitic Nematodes of Yam (Dioscorea spp.) in China, with Focus on Merlinius spp.

Simple SummaryPlant nematodes (PPNs) have been documented as economically important pests of yam in different parts of the world with Pratylenchus spp. and Meloidogyne spp. being the most widespread and destructive pests in Asia, causing significant yield losses. The primary inspiration for this study is the scarcity of information about nematode pests of yam in China and the fact that no previous study has looked into the prevalence, diversity, and integrative taxonomy of PPNs species in China cropping systems, as well as their consequences on yam cultivation. Therefore, the objectives of this study were to conduct a nematode study in south-eastern China to (i) record the prevalence and diversity of PPNs of cultivated yam with emphasis on the five prominent genera identified, and (ii) characterized morphologically, morphometrically, and molecularly Merlinius spp. The high prevalence of the Merlinius spp. revealed that the species may be more important to yam than previously thought. Conclusively, this study provided useful baseline PPNs data for yam in China. Hence, future study should focus on; developing innovative, environmentally friendly, and cost-effective nematode management strategies to control this pest that damage farmers’ yam fields in China, and constantly updating information of PPNs species found to allow proactive measures in terms of their spread and management.There is little information about nematode pests associated with yam in China. Between 2020 and 2021, surveys of yam fields were conducted to investigate the abundance and prevalence of plant-parasitic nematodes in major yam growing areas. A total of 110 bulk soil samples from the yam rhizosphere and 48 yam tubers were collected from seven counties in Jiangxi and Shandong provinces. Standard protocols were used to extract nematodes from soil and tubers and identified at the genus level. In this study, 16 species and 13 nematode genera were recorded. The five most prominent species on the yam rhizosphere according to mean population densities were Pratylenchus coffeae (291/individuals), Meloidogyne (262/individuals), Rotylenchulus reniformis (225/individuals), Merlinius (224/individuals), and Helicotylenchus dihystera (171/individuals). In the tubers, the three most prominent species were Pratylenchus coffeae (415/individuals), Meloidogyne (331/individuals), and Rotylenchulus reniformis (115/individuals). These species were verified with appropriate molecular analysis. The high prevalence of the ectoparasite (Merlinius spp.) on the rhizosphere of yam also revealed that Merlinius spp. May be more important to yam than previously thought. Morphological and molecular analyses further confirmed the identity of the species as Merlinius brevidens and were characterized for the first time on yam in China. Minor morphometrical differences (slightly longer body and stylet) were observed in Chinese populations of M. brevidens compared to the original description. Additionally, this study reveals that M. brevidens isolated from China showed a higher nucleotide sequence in the ITS region compared to M. brevidens populations from India. This finding provides baseline information on the nematode pest occurrence on yam in China and calls for effective management.

Trichostrongyloid nematodes in ruminants of northern Iran: prevalence and molecular analysis

BackgroundThis study was carried out to investigate the prevalence and analyze the molecular characteristics based on the internal transcribed spacer (ITS) 2 region of the ribosomal RNA (RNA) gene of trichostrongylid nematodes in different ruminants from Guilan province, northern of Iran.MethodsThe gastrointestinal tracts of 144 ruminants including 72 cattle, 59 sheep, and 13 goats were collected from an abattoir in Guilan province during July to September 2018. After isolation the helminths, male specimens were identified based on morphological parameters. PCR and partial sequencing of the ITS2 fragment were conducted. After phylogenetic analysis, the intraspecific and interspecific differences were calculated.ResultsThe prevalence of total infections with the nematodes was 38.9, 74.6 and 84.6% among cattle, sheep and goats, respectively. Eleven species of trichostrongylid nematodes including Haemonchus contortus, Marshallagia marshalli, Trichostrongylus axei, T. colubriformis, T. vitrinus, Ostertagia trifurcata, Teladorsagia circumcincta, Marshallagia occidentalis, O. lyrata, O. ostertagi, and Cooperia punctate were recovered from the ruminants. The most prevalent trichostrongyloid nematodes in cattle, sheep and goats were O. ostertagi (26.4%), M. marshalli (64.4%) and T. circumcincta (69.2%), respectively. Phylogenetic tree was discriminative for Trichostrongylidae family, while phylogenetic analysis of the ITS2 gene represented low variations and no species identification of Haemonchidae and Cooperiidae families.ConclusionsThis study suggests the high prevalence and species diversity of trichostrongyloid nematodes in different ruminants, indicating the importance of implement antiparasitic strategies in north regions of Iran. As well, this study showed that the ITS2 fragment is not a discriminative marker for Haemonchidae and Cooperiidae families, and investigation of other genetic markers such as mitochondrial genes would be more valuable for better understanding of their phylogenetic relationships.

Surveillance of soil-borne nematodiasis in Yancheng City from 2016 to 2020

To understand the prevalence of soil-transmitted nematode infections in Yancheng City from 2016 to 2020, so as to provide insights into the development of the scheme for further soil-transmitted nematodiasis surveillance. Soil-borne nematode infections were detected using the modified Kato-Katz method (two slides for one sample) among the permanent residents living in Yancheng City from 2016 to 2020, and Enterobius vermicularis infection was additionally detected among children at ages of 12 years and lower using the adhesive cellophane-tape perianal swab method. The prevalence and intensity of human soil-borne nematode and E. vermicularis infections were descriptively analyzed. A total of 51 259 person-time residents were detected for soil-borne nematode infections in Yancheng City from 2016 to 2020, and 48 egg-positives were identified, with a 0.09% prevalence. The soil-borne nematodes infecting residents included Ascaris lumbricoides, hookworm and Trichuris trichiura, with 0.04%, 0.05% and 0.002% prevalence rates of infections, and all infections were mild. There was a region-specific prevalence of soil-borne nematode infections in Yancheng City (χ2 = 18.21, P = 0.02), with the highest prevalence seen in Funing County (0.21%), while no infections were detected in Dafeng District for five successive years. The overall prevalence of E. vermicularis infections was 0.22% among children at ages of 12 years and lower in Yancheng City. The prevalence of soil-borne nematode infections appears a gradual decline in residents living in Yancheng City from 2016 to 2020, and is at an extremely low level. Further surveillance of soil-transmitted nematodiasis requires to be intensified targeting key regions and populations to consolidate the control achievements.

Epigenetic regulation of SLC11a1 gene in horses infected with cyathostomins

Cyathostomins are the most prevalent nematode parasites of horses worldwide and the SLC11a1 gene has been found to modulate the host immune response against parasite infections. The objective of this work was to determine the DNA methylation profile of the SLC11a1 gene in naturally infected horses (n = 6) and correlate it with the cyathostomin fecal egg count (FEC). In silico analyzes showed two CpG islands, located in the body of the gene and DNA sequencing showed a statistically significant difference between the methylation profile of islands 1 and 2 (P < 0.0001). The data revealed that island 1 was hypermethylated (>95%), while island 2 was hypomethylated (<10%). Although there were no statistical differences in animals with low or high FEC in relation to methylation of island 1 (P = 0.177) or island 2 (P = 0.231), the analysis of island 2 showed a pattern in which samples with higher FEC also presented higher methylation for that island. This data indicates a possible correlation between the cyathostome FEC and the increased methylation of island 2. Animals with a high methylation rate presented a decrease in FEC after 4 months. The preliminary results indicate for the first time the possibility of epigenetic regulation of the SLC11a1 gene in horses. Moreover, it is suggested that methylation of island 2 of the SLC11a1 cascade might indicate the prognostic of parasite infection. Epigenetic processes such as these might be used as biomarkers for identifying individual animals for target treatments and specific breeding purposes.

Development and evaluation of an indirect ELISA for detection of Teladorsagia circumcincta infection in sheep

BackgroundThe gastrointestinal helminth, Teladorsagia circumcincta, is one of the major health risks and production-limiting diseases in small ruminant populations, particularly in temperate regions. With the increasing importance of disease management and recruited anthelmintic resistant types, accurate approaches are needed for the diagnosis of the infection in the host. Due to uncertain results using faecal examinations, the ELISA method was indicated for the detection of nematode antigenic materials. Despite some promising results, problems were described in terms of test specificity and cross-reactions. Therefore, this study aimed to evaluate the IgG response to worm somatic and excretory/secretory (ES) products using western blot analysis and an indirect ELISA for the detection of T. circumcincta infection in sheep.ResultsBased on the immuno-reactivity analysis, immunogenic fractions with molecular weights (MWs) of approximately 60, 75 and 100 kDa were detected in somatic content and two antigens of about 63 and 75 kDa in ES material. Accordingly, a specific product at 75 kDa had the strongest reaction and appeared as the most common antigenic protein. In ELISA, all the sera from the infected sheep revealed the OD rates above the calculated cut-off value with about two-fold greater average. Negative control samples were also specifically recognized with the mean OD rate of about 1/3 of the estimated cut-off value. The cross-reaction test, using rabbit anti-T. circumcincta IgG, did not show reactivity with the ES antigens of other prevalent nematodes including Haemonchus contortus, Protostrongylus rufescens and Marshallagia marshalli. In contrast, a strong positive reaction was observed with the somatic antigens of M. marshalli.ConclusionsThe results of this study indicated that the indirect ELISA method using the ES content enables distinguishing the T. circumcincta infected sheep with high specificity. Those antigenic ES peptides with 63 and particularly 75 kDa MWs should be further investigated due to the potential for serological diagnostic methods and immunoprotective targets in the host.

DIAGNÓSTICO MOLECULAR DA RESISTÊNCIA DE HAEMONCHUS CONTORTUS AO GRUPO DOS BENZIMIDAZÓIS EM OVINOS E CAPRINOS NO ESTADO DE PERNAMBUCO, BRASIL

Sheep and goats suffer heavy losses due to the high prevalence of gastrointestinal nematodes, mainly from the nematode Haemonchus contortus. The parasite causes high morbidity and mortality, even though, the indiscriminate use of chemicals to control H. contortus has favored the selection of multidrug resistance parasites. Molecular diagnosis of resistance to the benzimidazole (BZs) group is important to indicate substitute strategies of control. The aim of this study was to determine the presence of the mutation at position F200Y of the beta-tubulin gene in seven populations of H. contortus from sheep and goats’ farms from the state of Pernambuco, Brazil. Twenty adult H. contortus male worms were recovered for DNAextraction from naturally infected animals, from farms from Recife, Sairé, Camocim deSão Félix, Gameleira, Moreno, Bonito, and Serra Talhada. The primers forward: 5` AAT GCT TCC ACC CTT GTC CAT C 3’, and reverse: 5’ CAA CAA CGG GCA TGA AGA AG 3’ were used to search for the main codon (F200Y) of the beta-tubulin gene to determine BZ resistance. The NC1/ITS-2 forward: 5’ ACG TCT GGT TCA GGG GTT TT 3’ and reverse: 5’ TTA TCT GTT TTT CCT GCC CT 3’ primers were used for confirming H. contortus species. A questionnaire was applied to obtain information on management practices, including the frequency of BZs use. The sequences from the NC1/ITS-2 confirmed the presence of H. contortus from all samples. The F200Y mutation responsible for BZ resistance (TTC/TAC) in H. contortus was found only in the samples from Sairé, as the TTC codon varied from 55.6 to 85.7%. In relation to the questionnaire, producers revealed the absence of quarantine for newly arrived animals; high drug treatment frequency (60-days interval); treatment of the whole flock; the visual estimation of the weight of the animals for dose determination; and high drug rotation. It was also mentioned the lack of veterinary assistance with no use of fecal exams. Even though, all these factors may be essential to increase parasite selection pressure, it was not possible to determine which of those showed a higher risk due to the high number of variables and the small number of participants. This is without any doubt one of the great difficulties to correlate phenotypic drug efficacy data (ex. FECRT) and genotypic-related (ex. PCR) resistance markers in helminths. We have included some risk factors reported by the farmers from Pernambuco and their influences in the process of drug selection, as well as a few strategies to mitigate this situation. The present report constitutes the first record of a molecular diagnosis of the mutation F200Y that confers resistance to the BZ group in ruminants in the state of Pernambuco, Brazil.

Study on Prevalence of Major Gastrointestinal Nematodes of Sheep in Wayu Tuka and Diga District, Oromia Regional State

Aim This study was devised to be conducted to determine the prevalence and identify the major gastrointestinal nematode parasites based on fecal examination. Methods A cross-sectional study was carried out to determine the prevalence and associated factors with ovine gastrointestinal nematode infestation by fecal examination of 384 sheep from Wayu Tuka and Diga district, Eastern Oromia regional state. Results Out of the total 384 sampled sheep, 169 (44.0%) had been infected with gastrointestinal nematode parasite. Haemonchus species were the most frequently (20.8%) recovered nematode eggs followed by Trichostrongylus (13.0%) and Nematodirus (10.2%). There was no significant difference (p&gt;0.05) in prevalence between age groups and sex. Sheep with poor body condition had a significantly higher prevalence of gastrointestinal nematode parasite (p&lt;0.05) than those sheep in moderate or good body condition. There was no significant association between the gastrointestinal nematode infection in animals of different ages and sex groups. Conclusion The study shows that the gastrointestinal nematode parasite was a major important health problem and impact on the production of sheep in the study area. Therefore, a detailed study should be conducted to identify the parasite at the species level and special consideration should be taken on the management of sheep in poor body condition to reduce the burden of gastrointestinal nematodes.

A Comparison of the Prevalence of the Parasites of the Digestive Tract in Goats from Organic and Conventional Farms.

Simple SummaryThe presence of gastrointestinal parasites such as coccidia (protozoa), gastrointestinal nematodes, flukes, and tapeworms are a considerable problem in goat keeping. Parasitic infections cause a deterioration of animal health, delay in growth rate, weight loss, reduced milk production, and miscarriages. The aim of the study was to compare the prevalence and intensity of parasitic infections observed in the digestive tracts of goats kept on organic and conventional farms. Our findings indicate that conventional goat herds demonstrate a similar prevalence of parasitic diseases as organic herds. Nevertheless, the prophylactic programs used to combat parasitic infections in both types of farms appear ineffective and require improvement. There is a need for goat herds to be covered by ongoing parasitological monitoring, including parasitological testing before and after the pasture season, to detect carriers and shedders of parasite eggs, oocysts, and cysts. It is also recommended that keepers employ rotational or intensive rotational grazing methods and take care to ensure the hygiene of animal quarters and livestock rooms. Furthermore, accurate diagnosis of parasitic infections, as well as effective monitoring and prophylaxis, are essential for keeping goat herds free from parasitic infections.The aim of the study was to compare the prevalence and intensity of gastrointestinal parasitic infections in goats kept on organic (n = 76) and conventional farms (n = 82). In general, a higher prevalence of some gastrointestinal parasitic infections was found in the conventional farms compared to the organic farms: the mean prevalence of Eimeria spp. was 85.4% in conventional farms and 77.6% in organic farms, that of Fasciola hepatica was 6.10% in conventional farms and 2.63% in organic farms, and that of Moniezia expansa was 31.7% and 17.1%, in conventional and organic farms, respectively. Both farm types demonstrated a similar mean prevalence of nematodes (80.3 vs. 84.2%). Conventional farms demonstrated a significantly higher intensity of infection with E. arloingi, Haemonchus spp., Nematodirus spp. and Moniezia expansa compared to organic farms. They also demonstrated a higher intensity of infection with Eimeria spp. than organic farms. The prophylactic programs used to combat parasitic infections in both types of farms appear ineffective and require improvement. There is a need for goat herds to be covered by ongoing parasitological monitoring. It is also recommended that keepers employ rotational or intensive rotational grazing methods and take care to ensure the hygiene of animal quarters and livestock rooms.

Multiple drug resistance in hookworms infecting greyhound dogs in the USA

Ancylostoma caninum is the most prevalent nematode parasite of dogs. We confirmed multiple-drug resistance (MDR) in several A. caninum isolates to all anthelmintic drug classes approved for the treatment of hookworms in dogs in the USA. Cases of MDR hookworms appear to be highly overrepresented in greyhounds. The aims of this study were to evaluate the drug-resistant phenotypes and genotypes of the A. caninum infecting greyhounds. Fecal samples from greyhounds of the USA were acquired from two greyhound adoption kennels, one active greyhound racing kennel, and three veterinary practices. Fecal egg counts (FECs) were performed on fecal samples from 219 greyhounds, and despite treatment with anthelmintics, the mean FEC was 822.4 eggs per gram (EPG). Resistance to benzimidazoles and macrocyclic lactones were measured using the egg hatch assay (EHA) and the larval development assay (LDA), respectively. We performed 23 EHA and 22 LDA on either individual or pooled feces, representing 54 animals. Mean and median IC50 and IC95 values for the EHA were 5.3 μM, 3.6 μM, and 24.5 μM, 23.4 μM, respectively. For the LDA, the median IC50 value was >1000 nM. These values ranged 62–81 times higher than our susceptible laboratory isolate. Only post-treatment samples were available. For samples collected <10 days post-treatment with albendazole, moxidectin, or a combination of febantel-pyrantel-moxidectin, the mean FEC were 349, 333, and 835 EPG, respectively. We obtained DNA from hookworm eggs isolated from 70 fecal samples, comprised of 60 individual dogs and 10 pools. Deep sequencing of the isotype 1 β-tubulin gene only revealed the presence of the F167Y (TTC>TAC) resistance polymorphism in 99% of these samples. These clinical, in vitro, and genetic data provide strong evidence that greyhound dogs in the USA are infected with MDR A. caninum at very high levels in prevalence and infection intensity.

Screening of Rhizosphere Bacteria and Nematode Populations Associated with Soybean Roots in the Mpumalanga Highveld of South Africa.

Soybean is among South Africa’s top crops in terms of production figures. Over the past few years there has been increasingly more damage caused to local soybean by plant-parasitic nematode infections. The presence of Meloidogyne (root-knot nematodes) and Pratylenchus spp. (root lesion nematodes) in soybean fields can cripple the country’s production, however, little is known about the soil microbial communities associated with soybean in relation to different levels of Meloidogyne and Pratylenchus infestations, as well as the interaction(s) between them. Therefore, this study aimed to identify the nematode population assemblages and endemic rhizosphere bacteria associated with soybean using Next Generation Sequencing (NGS). The abundance of bacterial genera that were then identified as being significant using linear discriminant analysis (LDA) Effect Size (LEfSe) was compared to the abundance of the most prevalent plant-parasitic nematode genera found across all sampled sites, viz. Meloidogyne and Pratylenchus. While several bacterial genera were identified as significant using LEfSe, only two with increased abundance were associated with decreased abundance of Meloidogyne and Pratylenchus. However, six bacterial genera were associated with decreased Pratylenchus abundance. It is therefore possible that endemic bacterial strains can serve as an alternative method for reducing densities of plant-parasitic nematode genera and in this way reduce the damages caused to this economically important crop.

MULTIDRUG RESISTANCE OF SHEEP GASTROINTESTINAL NEMATODES IN BAKRAJO DISTRICT, NORTH IRAQ TO ALBENDAZOLE, IVERMECTIN, AND LEVAMISOLE

A survey including 25 sheep farms in Bakrajo District, Sulaymaniyah, Iraq, was conducted to determine anthelmintic resistance (AR) against albendazole, ivermectin, and levamisole. Fecal Egg Count Reduction Test (FECRT) was used to accomplish this goal. Forty 6–24 month-old sheep of mixed sexes were selected from each farm and randomly divided into four groups. One group served as the untreated control, and the other groups orally administered the recommended doses of the tested drugs. Multidrug resistance against all three drugs was present in 8 of 25 farms (32%). Also, resistance to albendazole and ivermectin was detected on one farm. Albendazole was the most effective anthelmintic agent. Resistance to ivermectin was significantly higher than levamisole and albendazole. Larval cultures revealed that Trichostrongylus spp., Nematodirus spp., and Trichuris spp. were the prevalent gastrointestinal nematodes in the study area. The nematode genera were also detected in the posttreatment larval cultures. It is concluded that AR to albendazole, ivermectin, and levamisole is widespread in sheep in Bakrajo District, north Iraq. This resistance is mainly caused by the emergence of resistant Trichostrongylus and Nematodirus spp.

Prevalence of gastrointestinal parasites in cattle in Kalasin Province, Thailand.

Background and Aim:Parasitic infections are one of the major problems to the production of cattle in Thailand. The study was conducted to determine the prevalence of gastrointestinal (GI) parasites of cattle in Kalasin Province, Thailand.Materials and Methods:A total of 333 fecal samples of cattle were collected directly from the rectum. The fecal samples were subjected to formalin-ethyl acetate concentration methods for examination. The eggs or oocysts were identified based on the morphology and size of the eggs or oocysts.Results:Out of 333 fecal samples examined, 320 were found positive for GI parasitic infections with a prevalence of 96.09%. Overall, among the prevalence of nematodes, trematodes, and protozoa, the most prevalent parasites were Strongyle-type 278 (84.24%), followed by Strongyloides spp. 54 (16.36%) and Trichuris spp. 75 (22.73%), while Protozoan oocyst recorded Eimeria spp. amounted to 131 (39.7%). Fasciola spp. and Paramphistomum spp. were 67 (20.30%) and 81 (24.55%), respectively. Most of the positive fecal samples were infected with the double infection which has the highest prevalence rate of about 40.24%, followed by single, three, and 4-5 types of parasites 30.63, 16.82, and 7.21%, respectively.Conclusion:This study suggests that Kalasin Province is highly endemic for GI parasites and this area may be an important source for an outbreak. Therefore, every household should deworm its cattle and eliminate and control snails as intermediate hosts. Findings from this study provide information that will assist in improving the cattle in Kalasin Province for better production and higher profitability.

Canine Gastrointestinal Nematodiases and Associated Risk Factors in Kigali City, Rwanda.

Canine nematodes pose a public health risk to humans and livestock; however, the prevalence of canine nematodiases in Rwanda is unknown. This study aimed at determining the prevalence of canine nematodiases and identifying the risk factors for such infections in Kigali, the capital city of Rwanda. A cross-sectional study involved 93 dogs selected across Kigali city. Faecal samples were collected from apparently healthy dogs, and nematode eggs were identified and quantified using the McMaster technique. Risk factors for canine nematodiases were analysed by a multivariable binary logistic regression model. The overall prevalence of gastrointestinal (GI) nematodiases in dogs was 33.3% (95% CI: 23.8–42.9). The most prevalent species was Ancylostoma spp with 32.3% (95% CI: 22.8–41.8). Nearly 38.7% and 3.2% of the dogs infected with Ancylostoma spp and Toxocara canis had high egg counts per gram (EPG) of faeces (≥550), respectively. Approximately 96.8% of dogs infected with nematodes had monoinfection. Logistic regression analysis showed that dog's age (1 to 2.5 years old), location (Gasabo and Kicukiro districts), and feeding practices were significantly associated with prevalence of canine nematodiases. In particular, the adjusted odds ratio (AOR) was more than 5 times higher for dogs fed on uncooked animal products and leftovers from households and restaurants compared to those who ate food prepared for them. The AOR was also about 16 times higher for dogs that scavenged and ate leftovers from households compared to those who ate food prepared for them. The findings of this study indicate that the prevalence of GI nematodes in domestic dogs in Kigali city, Rwanda, was 33.3% (95% CI: 23.8–42.9). The identified nematodes, namely, Ancylostoma spp. and Toxocara canis, are zoonotic, and dogs and humans are at risk of contracting these nematodes. The factors associated with canine GI nematodes in Kigali city include feeding practices and the dog's age and location (district). Dog owners need to rethink procedures for deworming and feeding their dogs. Again, the public should be made aware of the role of dogs in transmitting zoonotic nematodes to humans.

High prevalence and intensity of fish nematodes with zoonotic potential in the Brazilian Amazon, including a brief reflection on the absence of human infections

This study aimed to characterize the prevalence, mean abundance, and mean intensity of potential fish-borne zoonotic nematode larvae infecting the predator fish Hoplias aff. malabaricus from the Tapajós River, in the municipality of Santarém, in the Brazilian Amazon. After capture, the specimens of H. aff. malabaricus were analyzed for infection by Contracaecum sp. and Eustrongylides sp. third-stage larvae, and the prevalence, mean abundance, and mean intensity were calculated. A literature search was carried out to clarify the relationship between these indicators and eventual human cases of infection in the Amazon region. Third-stage larvae of nematodes of the Contracaecum and Eustrongylides genera were found in the specimens of H. aff. malabaricus sampled from the Tapajós River. The prevalence of Contracaecum larvae was 100%, while its mean abundance and mean intensity were both 54.8 larvae/fish. The prevalence of Eustrongylides larvae was 62.9%, and its mean abundance and mean intensity were 1.8 and 2.8 larvae/fish, respectively. Despite the high prevalence and intensity values, there are no cases of human infection by these nematode larvae in the Brazilian Amazon reported. The absence of human infections by these nematode larvae in the Brazilian Amazon despite the high prevalence/intensity of Contracaecum and Eustrongylides larvae and the high consumption of fish in the region, is most probably due to the fact that the local populations do not eat raw or undercooked fish. However, it is noteworthy that the absence of zoonotic cases in the region is based only on the examination of the available published papers. A better knowledge of the situation would require surveying hospitals and clinics, and data from the region’s medical treatment facilities. However, the authors consider that cases of human infection, if any, are extremely rare, mainly due to the eating habits of the local population. KEY WORDS: Amazon basin; freshwater fish; public health; parasitic infection; zoonosis.

Effect of Agro-ecological Zone, Age, and Sex on Prevalence and Intensity of Gastrointestinal Parasites in Donkeys in Maseru District, Lesotho

Gastrointestinal parasites are considered to be silent killers of animals. The objective of the current study was to determine the effect of the agro-ecological zone, age, and sex on the parasite prevalence and fecal egg/oocyst count in donkeys residing in Lesotho. A total number of 720 fecal samples were collected rectally from 120 indigenous donkeys that were randomly selected from the highlands, foothills, and lowlands of Maseru district, Lesotho. The fecal samples were collected every two months for one year and examined using the floatation technique. The overall prevalence for nematodes, coccidia, and cestodes in donkeys were 87.78%, 4.31%, and 1.53%, respectively. The highest nematode prevalence and intensity were detected in the donkeys of highlands. The coccidian infection was lower in the lowlands while cestodes infection was more prevalent in the foothills. Donkey’s age had an impact on the nematode fecal egg load but did not affect the prevalence of nematodes in donkeys. Age did not significantly affect the prevalence and fecal egg/oocyst count of cestodes and coccidia. Male donkeys had a higher prevalence and fecal egg count of cestodes. In conclusion, the nematodes were found to be the major gastrointestinal parasites of donkeys in the Maseru district. Therefore, there is a need to design a sustainable strategy aimed at controlling the gastrointestinal parasites in donkeys.

Antinematode Activity of Abomasum Bacterial Culture Filtrates against Haemonchus contortus in Small Ruminants.

Simple SummaryHaemonchus contortus is an important gastrointestinal nematode parasite of the tropical and sub-tropical regions that cause haemonchosis in small ruminants like goats and sheep. It causes low production, reduced growth and may cause death of the infected animals. Due to the resistance development and environmental issues, the use of anthelmintics can be replaced with biological control, which is an environment friendly alternative. In the present study, three bacteria viz; Comamonas testosteroni, C. jiangduensis and Pseudomonas weihenstephanesis showed significant effect on nematode mortality and egg hatch inhibition. It was also observed that the anthelmintic activity of these bacteria was dose dependent, where 100% bacterial metabolite concentration showed the highest activity. It is suggested that these bacteria may included in the integrated nematode management.Haemonchosis is a parasitic disease of small ruminants that adversely affects livestock production. Haemonchus contortus is one of the most prevalent nematode parasites that infect the abomasum of small ruminants. This parasite reduces milk production, overall growth and sometimes causes the death of the infected animals. The evaluation of the biocontrol potential of some abomasum bacterial isolates against H. contortus is investigated in this study. Out of which, three isolates—Comamonas testosteroni, Comamonas jiangduensis, Pseudomonas weihenstephanesis—show significant effect against the nematode L3, adult, and egg hatch inhibition assays. Various concentrations of metabolites from these bacteria are prepared and applied in different treatments compared with control. In the case of adult mortality assay, 50% metabolites of C. testosteroni and P. weihenstephanesis show 46% adult mortality, whereas C. jiangduensis shows 40% mortality. It is observed that decreasing the concentration of bacterial metabolite, lowers nematode mortality. The minimum nematode mortality rate is recorded at the lowest filtrates concentration of all the bacterial isolates. The same trend is observed in egg hatch inhibition assay, where the higher concentration of bacterial culture filtrates shows 100% inhibition of H. contortus egg. It is concluded that the effect of bacterial culture filtrates against H. contortus is dose-dependent for their activity against nematode L3, adult, and inhibition of egg hatchment.

Symbiosis of the millipede parasitic nematodes Rhigonematoidea and Thelastomatoidea with evolutionary different origins

BackgroundHow various host–parasite combinations have been established is an important question in evolutionary biology. We have previously described two nematode species, Rhigonema naylae and Travassosinema claudiae, which are parasites of the xystodesmid millipede Parafontaria laminata in Aichi Prefecture, Japan. Rhigonema naylae belongs to the superfamily Rhigonematoidea, which exclusively consists of parasites of millipedes. T. claudiae belongs to the superfamily Thelastomatoidea, which includes a wide variety of species that parasitize many invertebrates. These nematodes were isolated together with a high prevalence; however, the phylogenetic, evolutionary, and ecological relationships between these two parasitic nematodes and between hosts and parasites are not well known.ResultsWe collected nine species (11 isolates) of xystodesmid millipedes from seven locations in Japan, and found that all species were co-infected with the parasitic nematodes Rhigonematoidea spp. and Thelastomatoidea spp. We found that the infection prevalence and population densities of Rhigonematoidea spp. were higher than those of Thelastomatoidea spp. However, the population densities of Rhigonematoidea spp. were not negatively affected by co-infection with Thelastomatoidea spp., suggesting that these parasites are not competitive. We also found a positive correlation between the prevalence of parasitic nematodes and host body size. In Rhigonematoidea spp., combinations of parasitic nematode groups and host genera seem to be fixed, suggesting the evolution of a more specialized interaction between Rhigonematoidea spp. and their host. On the other hand, host preference of Thelastomatoidea spp. was not specific to any millipede species, indicating a non-intimate interaction between these parasites and their hosts.ConclusionsThe two nematode superfamilies, Rhigonematoidea and Thelastomatoidea, have phylogenetically distinct origins, and might have acquired xystodesmid millipede parasitism independently. Currently, the two nematodes co-parasitize millipedes without any clear negative impact on each other or the host millipedes. Our study provides an example of balanced complex symbioses among parasitic nematodes and between parasitic nematodes and host millipedes, which have been established over a long evolutionary history.

Risk Assessment of Human Consumption of Meat From Fenbendazole-Treated Pheasants

Fenbendazole is a benzimidazole-class anthelmintic that is used for the control of immature and adult stages of internal parasites, such as nematodes and trematodes, in domestic food-animal species. It is not approved by the United States Food and Drug Administration for treating pheasants despite Syngamus trachea being one of the most prevalent nematodes that parasitize pheasants. Because it is a highly effective treatment, e.g., 90% effectiveness against S. trachea, and there are very few alternative therapeutic options, this anthelminthic is used in an extra-label manner in the pheasant industry, but few studies have been conducted assessing risks to humans. Therefore, we conducted a risk assessment to evaluate the potential repeat-dose and reproductive, teratogenic, and carcinogenic human risks that may be associated with the consumption of tissues from pheasants that were previously treated with fenbendazole. We conducted a quantitative risk assessment applying both deterministic and stochastic approaches using different fenbendazole sulfone residue limits (tolerance, maximum residue limits, and analytical limit of detection) established in different poultry species by the Food and Drug Administration, the European Medicines Agency, and other regulatory agencies in Japan, Turkey, and New Zealand. Our results show that fenbendazole poses minimal risk to humans when administered to pheasants in an extra-label manner, and a comparison of different fenbendazole sulfone residue limits can help assess how conservative the withdrawal interval should be after extra-label drug use.