Distributions and Geographical Relationships of the Polygyrid Land Snails (Mollusca, Gastropoda, Polygyridae) of Arkansas

The Arkansas distributions of land mollusks of the family Polygyridae are presented based on the results of a state-wide survey and a critical review of published and unpublished locality records. Six of the 45 species previously recorded for Arkansas are excluded because they were misidentified, do not have established populations in the state, or are found only as fossils. Four others are not mapped because of a lack of recent distributional data or because the specific status of a form is unclear. There is a predominant pattern of occurrence limited to the northern, northwestern, or western parts of the state. The northwest has rock outcrops, including the limestone and dolomite outcrops of the Ozark Mountains, extensive broadleaf woodland cover, and has suffered less disturbance from agriculture than the southeast, which results in more suitable land mollusk habitats in the northwest. Secondary patterns are apparent for species that are of widespread or sporadic distribution throughout the state, or found only in the eastern part of the state. Compared to adjoining states, Arkansas has a high diversity of polygyrid snails, exceeded only by Tennessee (59 species) and Texas (40 species). The highest number of co-occurrences is between Arkansas and Missouri (94.1%) and Arkansas and Oklahoma (92.3%). Arkansas shares 36.9% of species with states that border the eastern side of the Mississippi River and 63.1% with states that border the western side of the river. These data illustrate the dominance of the Ozark/Boston Mountains fauna on Arkansas land snail distribution plus what could be regarded as a secondary mid-western element

Revised List of Arkansas Terrestrial Mollusks with Notes on the Geographic Distribution of Species

A revised list of of Arkansas terrestrial mollusks is presented, based on the authors\u27 collections, incorporating data from the scientific literature and taking into account recent changes in taxonomy and species concepts. 144 species are recorded for Arkansas, of which 127 represent the autochthonous fauna of the state. The biogeographical position of Arkansas is reflected in its land mollusks, i.e., approximately 40% of Arkansas species are also widely distributed in the United States east of the Rocky Mountains, 12% are more widely distributed to the north, 11% are typical of the Gulf Coastal Plain, 14% form a Mid Western assemblage and 18% are endemic to the Ouachita-Ozark regions of Arkansas, Oklahoma and Missouri. The remaining 5% are species for which the geographic distribution is unclear. Diversity of Arkansas land mollusks is apparently due to the conjunction of these geographical zones within the state. Taxonomic problems exist for the genera Mesomphix and Paravitrea (family Zonitidae) and Succinea (family Succineidae) in Arkansa

Copro-antigen capture ELISA for the detection of Teladorsagia (Ostertagia) circumcincta in sheep: improvement of specificity by heat treatment

A copro-antigen capture ELISA for the detection of Teladorsagia circumcincta infection in sheep was developed and evaluated. Experiments with faeces from worm-free sheep, that had been spiked with known concentrations of excretory-secretory (E–S) antigen indicated that a positive signal was generated with 180 ng of E–S/ml. A nested design, based on 8 infected and 8 worm-free sheep, was employed to assess the stages during sample preparation contributing to variation in signal from the assay. This showed that 87% of the variance in the optical density readings (ODs) was directly explained by infection status. Variation between individual sheep within infection groups, and between samples at various stages in the assay, collectively accounted for the remaining variance. Initial evaluation of specificity using faeces from animals carrying a range of monospecific infections indicated cross-reactivity with Haemonchus contortus and Nematodirus spathiger. However, by treating the supernatant from faeces for 20 min at 100°C, the cross-reactive signal was eliminated whilst the specific signal was largely preserved. Heat treatment of faeces from 12 non-infected sheep, 12 sheep with T. circumcincta and 6 with H. contortus resulted in sensitivity being increased from 66.7 to 85.7%, and specificity from 62.5 to 87.5%. OD values showed a significant positive relationship with adult worm burdens, although at low infection intensities there was some overlap between infected and worm-free animals. We discuss the application of CC-ELISAs in facilitating selective chemotherapy of sheep, as a means of avoiding the development of anthelmintic resistance in pastoral regions where sheep are farmed on a large scale

Cross-sectional study of Fasciola gigantica and other trematode infections of cattle in Edu Local Government Area, Kwara State, North-central Nigeria

BACKGROUND: Trematode infections of livestock are of global veterinary and public health importance causing serious economic losses. Majority of data on burden of trematode infections in Nigeria are based on abattoir surveys and there are very few data on herd level risk factors. The present study investigated the prevalence of, and herd level risk factors for, fasciolosis and other trematode infections in cattle in Edu Local Government Area (LGA). METHODS: A cross-sectional survey used two-stage study design to investigate cattle belonging to 65 households. Two questionnaires were administered for household-level and individual cattle-level data. Faecal and blood samples were obtained from the cattle. Logistic regression analyses were performed to determine risk factors for infections. RESULTS: Of 686 faecal samples analysed, 74.9 %, 16.1 %, 7.3 % and 1.2 % were positive for infections with Fasciola gigantica, paramphistomes, Dicrocoelium hospes and Schistosoma bovis respectively. Fasciola gigantica had higher prevalence in adult cattle (77.3 %) than weaners (62.5 %). Majority of co-infections was a combination of F. gigantica with paramphistomes 84/130 (64.6 %). Most (58.9 %) of the cattle belonged to FAMACHA© score 2. The mean packed cell volume (PCV) was 34.4 %. The sensitivity and specificity of FAMACHA© for anaemia (PCV < 24 %) were 18.2 and 96.9 %, respectively. Positive correlation was obtained between faecal egg counts for F. gigantica and paramphistomes (R = 0.15, P = 0.0001). Adult cattle were more likely to be infected with F. gigantica (odds ratio, OR: 1.94; Confidence Interval, CI: 1.19–3.16) than weaners. Cattle belonging to household heads aged between 40–59 years were more likely infected with paramphistomes (OR: 1.95; CI: 1.02–3.74) than those belonging to other age groups. Cattles from herds with size ≥ 100 were more likely infected with D. hospes than those from smaller herds (OR: 6.98; CI: 2.94–16.6). CONCLUSION: This study revealed high prevalence of infection with F. gigantica in Kwara State. The co-infections by F. gigantica and paramphistomes with a positive correlation should be considered during anthelmintic therapy. There is a need to optimise and validate the FAMACHA© for use in cattle based on breeds and variation in colour of ocular mucous membrane. Risk factors identified could assist in tailoring control strategies for various trematode infections to particular groups of farmers and cattle. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1737-5) contains supplementary material, which is available to authorized users

Suscetibilidade de linhagens de Biomphalaria glabrata a cepas de Schistosoma mansoni

Com duas linhagens de Biomphalaria glabrata foi estudada a suscetibilidade de cinco cepas de Schistosoma mansoni resistentes e suscetíveis a esquistossomicidas. Três cepas do trematódeo oriundas de Porto Rico apresentaram desenvolvimento mais lento e menor índice de infecção em B. glabrata brasileira quando comparados com o comportamento de duas cepas de S. Mansoni provenientes do Brasil. Por outro lado, as cepas brasileiras do parasita desenvolve ram bem e infectaram mais de 90% dos exemplares de B. glabrata portorriquenhos. Entre os resultados, ressalta-se que cepas resistentes a esquistossomicidas poderão ser introduzidas por pacientes em diferentes áreas geográficas como Brasil e Porto Rico.Five strains of Schistosoma mansoni resistant and susceptible to schistosomicides were studied for infectivity of 2 strains of Biomphalaria glabrata one of Puerto Rican origin and the other of Brazilian origin. Puerto Rican strains of S. Mansoni developed more slowly and had a lower infectivity in Brazilian B. glabrata than did the Brazilian S. mansoni. However, Brazilian S. Mansoni developed as well in Puerto Rican snails as in Brazilian snails, indicating that drug resistant strains could easily be moved by travel of infected persons from one area to another

Epidemiology of strongyle nematode infections and first report of benzimidazole resistance in Haemonchus contortus in goats in South Darfur State, Sudan

Background Since pastoralists in South Darfur, Sudan, had complained about lack of albendazole (ABZ) efficacy to control nematodes in goats, the frequency of infection with gastrointestinal helminths was studied before in vivo faecal egg count reduction tests (FECRT) were conducted using ABZ orally either at the dose recommended for sheep, 5 mg/kg body weight (bw) or at 10 mg/kg bw. Experiments included goats naturally infected with gastrointestinal nematodes or experimentally infected with local Haemonchus contortus isolates. Three study areas (Nyala, Beleil and Kass) were visited in autumn or winter. Results Out of 478 screened goats, 82.4% were infected with gastrointestinal helminths and 82% were shedding eggs of strongyle nematodes with 90% of the strongyle larvae representing Haemonchus spp. A FECRT using naturally infected goats (n = 225: 71 untreated, 104 and 50 treated with 5 and 10 mg ABZ/kg bw, respectively) detected reduced ABZ efficacy in Nyala and Kass. Paired and unpaired FECRT calculations detected reductions of 72–92% with samples taken at 8 days post treatment with 5 mg ABZ/kg bw and of 85–94% with 10 mg ABZ/kg bw. The FECRT based on day 14 post treatment samples showed reductions of 69–77% with 5 mg/kg and of 75–87% with 10 mg ABZ/kg bw. In Beleil, ABZ efficacy was 95%. In the egg hatch test EC50 values for Nyala and Kass ranged from 0.12–0.24 μg thiabendazole/ml, corresponding to benzimidazole resistant phenotypes. Only Haemonchus spp. larvae were present after treatments in coprocultures. When the efficacy was evaluated experimentally using isolates of H. contortus from Nyala and Kass, the 5 mg ABZ/kg dose revealed reductions of 76–78% on day 8 and of 62–70% on day 14 with the unpaired method. Using 10 mg ABZ/kg, the FECR was still only 77–82%. Conclusions Both, in vivo and in vitro methods detected resistant H. contortus populations in goats from South Darfur State. The time point 14 days post treatment was more sensitive for detection of ABZ resistance than 8 days post treatment. This is the first report on the occurrence of anthelmintic resistance in Sudan confirming that anthelmintic resistance selection is occurring in African subsistence farming systems

The comparison of FLOTAC, FECPAK and McMaster techniques for nematode egg counts in cattle

AbstractThree methods, FLOTAC, FECPAK and McMaster were compared for accuracy and sensitivity for counting numbers of nematode eggs in faeces of naturally infected cattle with high or low nematode egg counts. Only FLOTAC gave positive results for 12 replicates from pooled samples with low egg counts making it more sensitive than FECPAK (67%) and McMaster (41.7%). FLOTAC resulted in generally higher egg counts and lower coefficients of variation than the other two methods used. The reliability of FECPAK and McMaster is depended on the area under the slide counted. All three methods can be used for making decisions whether to treat but FLOTAC or Mini-FLOTAC should be used for faecal egg count reduction tests when lower egg counts are present

Trematode infections in cattle in Arumeru District, Tanzania are associated with irrigation

Background The relationship between the environment and infection of cattle with trematodes was studied at Arumeru District, Arusha Region, northern Tanzania. Randomly selected villages were grouped into three cattle management strata, (i) zero-grazing (ZZ) (ii) communal grazing without irrigation (ZC) and (iii) communal grazing with irrigation (ZCI). Methods Faecal samples were collected from 241 cattle, and processed using the Flukefinder® method. Snail intermediate hosts were collected with a snail scoop from the water bodies in the study villages and identified morphologically. Results The overall prevalence of F. gigantica, paramphistomes and S. bovis were 33%, 37% and 2% respectively. Prevalence for F. gigantica, paramphistomes, and S. bovis for each stratum were, zero-grazing (ZZ) (29.7%, 36.0% and 0%), communal grazing without irrigation (ZC) (6.3%, 15.0% and 3.8%) and communal grazing with irrigation (ZCI) (57.7%, 56.7% and 1.0%) respectively. The differences between strata were significant for F. gigantica (p < 0.001) and paramphistomes (p < 0.05) but not for S. bovis. Irrigation could account for the high prevalence of F. gigantica and paramphistomes in the ZCI stratum as compared to the ZZ and ZC strata. The higher prevalences of F. gigantica and paramphistomes in the ZZ stratum compared with the ZC stratum were unexpected and attributed to the practice of farmers in some ZZ stratum villages buying fodder for their cattle obtained from pastures in ZCI villages. Conclusion Trematode infections in cattle are prevalent in Arumeru District. Fasciola gigantica and paramphistomes are associated with grazing in areas with irrigation of crops. Zero-grazing of cattle does not necessarily prevent the risk of infection

Associations between trematode infections in cattle and freshwater snails in highland and lowland areas of Iringa Rural District, Tanzania

SUMMARYThe epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle wereFasciola gigantica28·2%, paramphistomes 62·8% andSchistosoma bovis4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude &gt; 1500 m) as compared with lowland (altitude &lt; 1500 m) areas and was statistically significant (P-value = 0·000) forF. giganticaand paramphistomes but not forS. bovis. The snails collected includedLymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculataandBellamya constrictawith a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology ofF. giganticaand paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.</jats:p