Temporal and spatial dynamics of Cryptosporidium parvum infection on dairy farms in the New York City Watershed: a cluster analysis based on crude and Bayesian risk estimates

<p>Abstract</p> <p>Background</p> <p><it>Cryptosporidium parvum </it>is one of the most important biological contaminants in drinking water that produces life threatening infection in people with compromised immune systems. Dairy calves are thought to be the primary source of <it>C. parvum </it>contamination in watersheds. Understanding the spatial and temporal variation in the risk of <it>C. parvum </it>infection in dairy cattle is essential for designing cost-effective watershed management strategies to protect drinking water sources. Crude and Bayesian seasonal risk estimates for <it>Cryptosporidium </it>in dairy calves were used to investigate the spatio-temporal dynamics of <it>C. parvum </it>infection on dairy farms in the New York City watershed.</p> <p>Results</p> <p>Both global (Global Moran's I) and specific (SaTScan) cluster analysis methods revealed a significant (p < 0.05) elliptical spatial cluster in the winter with a relative risk of 5.8, but not in other seasons. There was a two-fold increase in the risk of <it>C. parvum </it>infection in all herds in the summer (p = 0.002), compared to the rest of the year. Bayesian estimates did not show significant spatial autocorrelation in any season.</p> <p>Conclusions</p> <p>Although we were not able to identify seasonal clusters using Bayesian approach, crude estimates highlighted both temporal and spatial clusters of <it>C. parvum </it>infection in dairy herds in a major watershed. We recommend that further studies focus on the factors that may lead to the presence of <it>C. parvum </it>clusters within the watershed, so that monitoring and prevention practices such as stream monitoring, riparian buffers, fencing and manure management can be prioritized and improved, to protect drinking water supplies and public health.</p

Incidence of and risks associated with Giardia infections in herds on dairy farms in the New York City Watershed

<p>Abstract</p> <p>Background</p> <p>The primary aims of this study were to determine the incidence of <it>Giardia </it>infections in dairy herds on farms in the New York City Watershed region and to evaluate risk factors associated with infections. Because co-infections of <it>Giardia </it>and <it>Cryptosporidium </it>spp. are common in this population, we also evaluated the effect of herd infection status on <it>Giardia </it>infections.</p> <p>Methods</p> <p>Farms were grouped into three cohorts based on their prior infection status with <it>Giardia </it>and/or <it>Cryptosporidium </it>spp. The sampling plan included collecting fecal samples from all calves below 30 days of age and proportional sampling of calves, young stock, and adults. A total of 10,672 fecal samples were collected and analyzed for the presence of <it>Giardia </it>cysts using zinc sulfate flotation. Herds enrolled in the study were sampled seasonally for a study period of two years. The probability of shedding cysts past a certain age and the factors that influenced the likelihood of shedding were evaluated using survival analysis. Linear regression was used to evaluate factors that were associated with the intensity of shedding.</p> <p>Results</p> <p>The majority of <it>Giardia </it>infections occurred in calves within their first 180 days of age, with the most number of calves shedding <it>Giardia </it>cysts between 11 and 20 days of age. The incidence of shedding of <it>Giardia </it>cysts ranged from 0.0004 per animal day for cattle in the low risk cohort to 0.0011 per animal day for cattle in the high risk cohort. The likelihood of shedding was influenced by the prior infection status of the herd and the season of collection. Infected animals shed on average 9,658 cysts/gram and the intensity of shedding <it>Giardia </it>cysts varied significantly with the age (p < 0.0001) and the season of collection (p = 0.0151 for Spring).</p> <p>Conclusion</p> <p><it>Giardia </it>infections are common in dairy herds in the New York City watershed, particularly in calves less than 6 months of age. Seasonality may be an important factor in the perpetuation of infections based on changes in management practices corresponding to weather patterns of a particular season. A dairy herd's prior infection status with <it>Cryptosporidium </it>influences the likelihood of infection with <it>Giardia</it>.</p

Phosphorylated neurofilament H (pNF-H) as a potential diagnostic marker for neurological disorders in horses

The current study aimed at the investigating the potential use of phosphorylated neurofilament H (pNF-H) as a diagnostic biomarker for neurologic disorders in the horse. Paired serum and cerebrospinal fluid (CSF) samples (n = 88) and serum only (n = 30) were obtained from horses diagnosed with neurologic disorders and clinically healthy horses as control. The neurologic horses consisted of equine protozoal myeloencephalitis (EPM) (38 cases) and cervical vertebral malformation (CVM) (23 cases). Levels of pNF-H were determined using an ELISA. The correlation between CSF and serum concentrations of pNF-H was evaluated using Spearman's Rank test and the significance of the difference among the groups was assessed using a nonparametric test. Horses had higher pNF-H levels in the CSF than serum. Horses afflicted with EPM had significantly higher serum pNF-H levels in comparison to controls or CVM cases. The correlation between CSF and serum pNF-H levels was poor in both the whole study population and among subgroups of horses included in the study. There was significant association between the likelihood of EPM and the concentrations of pNF-H in either the serum or CSF. These data suggest that pNF-H could be detected in serum and CSF samples from neurologic and control horses. This study demonstrated that pNF-H levels in serum and CSF have the potential to provide objective information to help in the early diagnosis of horses afflicted with neurologic disorders

Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates in remote Peruvian Amazon

Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the modified agglutination test (MAT). These animals were hunted by subsistence hunters along the Yavarí-Mirín River, in the northeastern Peruvian Amazon. Blood samples were collected by hunters on filter papers. For determination of T. gondii antibodies, blood was eluted from filter papers, and a titer of 1:25 was considered indicative of exposure to T. gondii. Antibodies to T. gondii were found in 26 (31.0%) peccaries (Pecari tajacu, Tayassu pecari), six (17.1%) brocket deer (Mazama americana, Mazama gouazoubira), and four (40.0%) lowland tapir (Tapirus terrestris). We also introduced a modification to the MAT protocol that allows the extraction of fluid samples from several types of laboratory-grade filter paper, thus enabling researchers to easily adapt their approaches to the materials presented to them

Potential reservoir and associated factors for West Nile virus in three distinct climatological zones

West Nile virus (WNV) is a zoonotic single-strand RNA arbovirus (family Flaviviridae: Flavivirus), transmitted among avian hosts in enzootic cycles by a mosquito vector. The virus has a significant disease effect on humans and equines when it bridges into a cycle with various sequelae with epidemic potential. This study was carried out to identify the potential spectrum of WNV hosts in three geographic areas with climatologically distinct features: Malaysia, Qatar, and the United States of America (U.S.). Serum samples were collected from avian and mammal species suspected to be reservoirs for the virus at these areas in a cross-sectional epidemiologic study. The samples were tested for the presence of antibodies against the virus using an enzyme-linked immunosorbent assay. Data on putative risk factors were also collected and analyzed for significance of association with seropositivity using the logistic regression analysis. Among the tested avian and mammalian species, raccoons had the highest seroconversion rate (54%) followed by crows (30%), horses (27%), camels (10%), other avian species (7%), and canine species (3%). It was almost twice as likely to detect seroconversion among these mammalian and avian species in the fall in comparison to other seasons of the year. Only mammalian and avian species and seasons of the year were significantly associated with the likelihood of seroconversion to WNV when we controlled for other factors in the multivariate analysis. Our data from the U.S. showed that raccoons and camels are susceptible to infection by the virus and may play a role in the perpetuation of endemic foci for the disease

Evidence of West Nile virus infection in migratory and resident wild birds in west coast of peninsular Malaysia

West Nile virus (WNV) is a zoonotic mosquito-borne flavivirus that is harbored and amplified by wild birds via the enzootic transmission cycle. Wide range of hosts are found to be susceptible to WNV infection including mammals, amphibians and reptiles across the world. Several studies have demonstrated that WNV was present in the Malaysian Orang Asli and captive birds. However, no data are available on the WNV prevalence in wild birds found in Malaysia. Therefore this study was conducted to determine the serological and molecular prevalence of WNV in wild birds in selected areas in the West Coast of Peninsular Malaysia. Two types of wild birds were screened, namely migratory and resident birds in order to explore any possibility of WNV transmission from the migratory birds to the resident birds. Thus, a cross-sectional study was conducted at the migratory birds sanctuary located in Kuala Gula, Perak and Kapar, Selangor by catching 163 migratory birds, and 97 resident birds from Kuala Gula and Parit Buntar, Perak at different time between 2016 and 2017 (Total, n = 260). Blood and oropharyngeal swabs were collected for serological and molecular analysis, respectively. Serum were screened for WNV antibodies using a commercial competitive ELISA (c-ELISA) (ID Screen® West Nile Competition Multi-species ELISA, ID VET, Montpellier, France) and cross-reactivity towards Japanese Encephalitis virus (JEV) was also carried out using the JEV-double antigen sandwich (DAS) ELISA. Oropharyngeal swabs were subjected to one-step RT-PCR to detect WNV RNA, in which positive reactions were subsequently sequenced. WNV seropositive rate of 18.71% (29/155) at 95% CI (0.131 to 0.260) and molecular prevalence of 15.2% (16/105) at 95% CI (0.092 to 0.239) were demonstrated in migratory and resident wild birds found in West Coast Malaysia. Phylogenetic analyses of the 16 WNV isolates found in this study revealed that the local strains have 99% similarity to the strains from South Africa and were clustered under lineage 2. Evidence of WNV infection in resident and migratory birds were demonstrated in this study. As a summary, intervention between migratory birds, resident birds and mosquitoes might cause the introduction and maintenance of WNV in Malaysia, however the assumption could be further proven by studying the infection dynamics in the mosquitoes present in the studied areas

Vitamin E deficiency and risk of equine motor neuron disease

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