Low-intensity Infections Research Articles

Host age alters amphibian susceptibility to Batrachochytrium dendrobatidis, an emerging infectious fungal pathogen.

Parasites and pathogens are often aggregated in a minority of susceptible hosts within a population, with a majority of individuals harboring low infection intensities. However, determining the relative importance of host traits to explain this heterogeneity is a challenge. One ecologically important pathogen is Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis and has been associated with many amphibian population declines worldwide. For many hosts, post-metamorphic stages are generally more susceptible than the larval stage. Yet, examination of the effects of Bd infection at different ages within a life stage, has received little attention. This study investigated the hypothesis that recently-post-metamorphic frogs were more sensitive to chytridiomycosis than older frogs, and that sensitivity to Bd infection decreased as frogs aged. We examined this relationship with Pacific treefrogs (Pseudacris regilla) and red legged frogs (Rana aurora). Age had a strong effect on susceptibility to infection, infection intensity, and survival–but not in the directions we had predicted. In both host species, an increase in age was associated with frogs becoming more susceptible to Bd infection, harboring larger infection intensities, and greater risk of mortality. This suggests that the timing of Bd exposure may influence amphibian population dynamics.

An innovative and user-friendly scoring system for standardised quantitative interpretation of the urine-based point-of-care strip test (POC-CCA) for the diagnosis of intestinal schistosomiasis: a proof-of-concept study

The point-of-care strip assay for the detection of the schistosome Circulating Cathodic Antigen (POC-CCA) in urine has shown to be a user-friendly and sensitive alternative to stool microscopy for the diagnosis of Schistosoma mansoni infections. However, visual scoring of the test is by definition observer dependent and leads to discussion about the qualitative interpretation, in particular in low intensity infections when test lines tend to be weak. In order to standardise visual scoring, an innovative approach for semi-quantitative interpretation of the POC-CCA cassettes, called G-scores, was developed and evaluated. Urines (n = 110) from a S. mansoni endemic area were used to evaluate this new approach. Test lines of the POC-CCA were visually compared against the G-scores, i.e. a series of artificial cassettes containing inkjet-printed strips of different intensities in order to grade the POC-CCA test line on a scale of 1 to 10. A significant positive correlation (Spearman 0.660, p < 0.001) was observed between G-scores and eggs per gram of faeces. This proof-of-concept study demonstrates the usefulness of the G-scores for standardising the visual scoring of the POC-CCA urine strip assay. Several research groups have already indicated an interest in the G-scores for their field work. Further distribution of the cassettes, in particular when provided in combination with reference standards, will assist the wider schistosomiasis community in dealing with issues like batch-to-batch differences and interpretation of trace readings.

Attenuated Leishmania major Induce a High Level of Protec-tion against Leishmania infantum in BALB/c Mice

The current study aimed to investigate the possible cross-protective effects of attenuated L. major against L. infantum in BALB/c mice. This experimental study was performed in 2017 in Shiraz University of Medical Sciences, Shiraz, Iran. The attenuated strain of L. major was prepared by continuous weekly subculturing of the parasite. Forty-eight female BALB/c mice were divided into eight groups. Group 1 injected (ID) with wild type of L. major; group 2 injected (IV) with L. infantum; group 3 injected (ID) with attenuated L. major; group 4 injected (ID) with attenuated L. major, and after three weeks challenged (IV) with L. infantum; group 5 injected (IP) with attenuated L. major; group 6 injected (IP) with attenuated L. major, and challenged (IV) with L. infantum (IV); group 7 injected (IV) with attenuated L. major; and finally group 8 injected (IV) with attenuated L. major and after three weeks challenged (IV) with L. infantum. Forty-five days post-infection, the parasite load in the spleen and liver of the mice was determined as Leishman-Donovan units (LDU). The differences in mean of LDU of spleen between different groups were statistically significant (P<0.048). In addition, the differences in percent of infection in liver between pairwise comparisons of groups were statistically significant (P<0.05). The highest intensity of infection was observed in group 2 while low intensity of infection was seen in groups 3, 4 and 5. Live attenuated L. major can induce substantial protection against L. infantum, particularly when the parasites were injected intravenously.

Development and validation of a multiplexed-tandem qPCR tool for diagnostics of human soil-transmitted helminth infections.

Soil-transmitted helminths (STH) are a major cause of morbidity in tropical developing countries with a global infection prevalence of more than one billion people and disease burden of around 3.4 million disability adjusted life years. Infection prevalence directly correlates to inadequate sanitation, impoverished conditions and limited access to public health systems. Underestimation of infection prevalence using traditional microscopy-based diagnostic techniques is common, specifically in populations with access to benzimidazole mass treatment programs and a predominance of low intensity infections. In this study, we developed a multiplexed-tandem qPCR (MT-PCR) tool to identify and quantify STH eggs in stool samples. We have assessed this assay by measuring infection prevalence and intensity in field samples of two cohorts of participants from Timor-Leste and Cambodia, which were collected as part of earlier epidemiological studies. MT-PCR diagnostic parameters were compared to a previously published multiplexed qPCR for STH detection. The MT-PCR assay agreed strongly with qPCR data and showed a diagnostic specificity of 99.60–100.00% (sensitivity of 83.33–100.00%) compared to qPCR and kappa agreement exceeding 0.85 in all tests. In addition, the MT-PCR has the added advantage of distinguishing Ancylostoma spp. species, namely Ancylostoma duodenale and Ancylostoma ceylanicum. This semi-automated platform uses a standardized, manufactured reagent kit, shows excellent run-to-run consistency/repeatability and supports high-throughput detection and quantitation at a moderate cost.

Prevalence and risk factors of schistosomiasis and soil-transmitted helminthiases among preschool aged children (1\u20135\u2009years) in rural KwaZulu-Natal, South Africa: a cross-sectional study

BackgroundDespite efforts to control neglected tropical diseases (NTDs), schistosomiasis and soil-transmitted helminthiases remain widely prevalent in sub-Saharan Africa. Recent data suggest that these infections are prevalent among preschool aged children (PSAC) in poor communities. Evidence of schistosomiasis and soil-transmitted helminths (STH) infection patterns and prevalence among PSAC is essential for effective treatment and control programmes. The aim of the study was to determine the prevalence, intensity and risk factors of schistosomiasis and STH infection among PSAC in the Ingwavuma area of uMkhanyakude District, South Africa.MethodsA cross-sectional study was conducted among 1143 PSAC aged 1–5 years in 34 preschools and early childhood development (ECD) centres. Data on risk factors was collected using a semi-structured questionnaire. A Kruskal–Wallis test was used to compare the differences in infection intensity with age. Pearson Chi-square test and multivariate logistic regression were performed to assess the association between PSAC infection status, sociodemographic, household, water and sanitation variables and hygiene practices of PSAC and their caregivers.ResultsWe observed a low prevalence of Schistosoma haematobium (1.0%) and S. mansoni (0.9%). The prevalence of Ascaris lumbricoides (18.3%) was high compared to Trichuris trichiura (1.2%), hookworms (1.6%) and Taenia (6.4%). The odds of schistosome infection were lowest among PSAC under younger (15–24 years) caregivers (0.1, 95% CI: 0.02–0.54) and those who used tap water (0.3, 95% CI: 0.09–0.78) for domestic purposes. Schistosome infection was however higher among PSAC who bathed in river water (17.4, 95% CI: 5.96–51.04). STH infection on the other hand was lowest among PSAC who did not play in soil (0.1, 95% CI: 0.51–0.28), were from households that used tap water for domestic purposes (0.5, 95% CI: 0.27–0.80) and PSAC under the care of younger (25–35 years) caregivers (0.3, 95% CI: 0.10–0.75). The risk of STH infection was highest among PSAC who did not wash their hands with soap (3.5, 95% CI: 1.04–11.67) and PSAC whose nails were not trimmed (3.6, 95% CI: 1.75–7.26).ConclusionsThe findings show low prevalence and infection intensity of schistosomiasis and STH infection except A. lumbricoides among PSAC. Factors predicting schistosomiasis and STH infection among PSAC were related to caregivers’ age, educational status, water and hygiene practices. STH infection was exclusively associated with PSAC playing and handwashing habits. These findings highlight the need to include PSAC caregivers in schistosomiasis and STH prevention and control programmes.

Discrepancy between batches and impact on the sensitivity of point-of-care circulating cathodic antigen tests for Schistosoma mansoni infection

The Kato-Katz (KK) technique is the mainstay mapping tool for the diagnosis of Schistosoma mansoni infection, despite showing poor sensitivity in cases of low-intensity infections. As an alternative, a rapid point-of-care circulating cathodic antigen diagnostic test (POC-CCA) has been commercially developed that involves a simple urine assay to detect S. mansoni, rather than a stool-based parasitological examination. Although POC-CCA has proven to be a more sensitive test than KK, it is not yet clear how to interpret discordant results between the two tests, particularly for situations in which the KK result is positive and the POC-CCA result is negative. Thus, the objective of this study was to evaluate the degree of diagnostic variability between different POC-CCA batches with respect to results obtained with KK. For this purpose, we collected urine and stool samples of school-aged children from areas of low and moderate endemicity in Brazil, and compared different POC-CCA batches results with those of KK-positive individuals. We found a statistically significant difference between the results obtained from various POC-CCA batches using the same urine samples, regardless of the degree of endemicity and the intensity of infection in positive KK samples. In addition, there was poor agreement between the KK and POC-CCA results in some batches of the rapid test, resulting in false negatives. These findings raise concerns around quality control checks of POC-CCA, especially in light of the high cost and increasing reliance on this new diagnostic method as control programs move towards a goal of elimination.

MONITORING OF IXODIC TICKSIN THE CENTRAL REGION OF ARMENIA

Throughout 2015–2017 the peculiarities of activity, the timing of parasitization, the dynamics of numbers, as well as the life cycles of various background species of ticks were studied in various biotopes, in the Kotayk marz (region), in the central region of Armenia at altitudes of 1500 - 2000 a.s.l. It is noted that under conditions of intensive urbanization of the territory, in the absence of organized pastures, the species composition of ixodic ticks, parasitizing on farm animals, undergoes significant changes. With a relatively low intensity of infection of livestock, the species composition of ixodic ticks increased due to species, which are characterized by mountain-steppe and high-mountain habitats. This is explained by the fact that in order to find the best forage base, the cattle in the summer season is driven away to adjacent pastures, where the animal re-infection with ticks occurs.It is noted that the types of ticks that were not previously recorded in this area were found on livestock mainly in the offseason, during their overexposure in the stall mode. From year to year, synanthropization of these species is observed. The data obtained can be used when planning anti-tick measures in the region.

Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: A cluster-randomized controlled trial in rural Bangladesh.

BackgroundSoil transmitted helminths (STH) infect >1.5 billion people. Mass drug administration (MDA) effectively reduces infection; however, there is evidence for rapid reinfection and risk of potential drug resistance. We conducted a randomized controlled trial in Bangladesh (WASH Benefits, NCT01590095) to assess whether water, sanitation, hygiene and nutrition interventions, alone and combined, reduce STH in a setting with ongoing MDA.Methodology/Principal findingsIn 2012–2013, we randomized 720 clusters of 5551 pregnant women into water treatment, sanitation, handwashing, combined water+sanitation+handwashing (WSH), nutrition, nutrition+WSH (N+WSH) or control arms. In 2015–2016, we enrolled 7795 children, aged 2–12 years, of 4102 available women for STH follow-up and collected stool from 7187. We enumerated STH infections with Kato-Katz. We estimated intention-to-treat intervention effects on infection prevalence and intensity. Participants and field staff were not blinded; laboratory technicians and data analysts were blinded.Prevalence among controls was 36.8% for A. lumbricoides, 9.2% for hookworm and 7.5% for T. trichiura. Most infections were low-intensity. Compared to controls, the water intervention reduced hookworm by 31% (prevalence ratio [PR] = 0.69 (0.50,0.95), prevalence difference [PD] = -2.83 (-5.16,-0.50)) but did not affect other STH. Sanitation improvements reduced T. trichiura by 29% (PR = 0.71 (0.52,0.98), PD = -2.17 (-4.03,-0.38)), had a similar borderline effect on hookworm and no effect on A. lumbricoides. Handwashing and nutrition interventions did not reduce any STH. WSH and N+WSH reduced hookworm prevalence by 29–33% (WSH: PR = 0.71 (0.52,0.99), PD = -2.63 (-4.95,-0.31); N+WSH: PR = 0.67 (0.50,0.91), PD = -3.00 (-5.14,-0.85)) and marginally reduced A. lumbricoides. Effects on infection intensity were similar.Conclusions/SignificanceIn a low-intensity infection setting with MDA, we found modest but sustained hookworm reduction from water treatment and combined WSH interventions. Impacts were more pronounced on STH species with short vs. long-term environmental survival. Our findings suggest possible waterborne transmission for hookworm. Water treatment and sanitation improvements can augment MDA to interrupt STH transmission.Trial registrationNCT01590095.

Environmental DNA for improved detection and environmental surveillance of schistosomiasis.

Schistosomiasis is a water-based, infectious disease with high morbidity and significant economic burdens affecting >250 million people globally. Disease control has, with notable success, for decades focused on drug treatment of infected human populations, but a recent paradigm shift now entails moving from control to elimination. To achieve this ambitious goal, more sensitive diagnostic tools are needed to monitor progress toward transmission interruption in the environment, especially in low-intensity infection areas. We report on the development of an environmental DNA (eDNA)-based tool to efficiently detect DNA traces of the parasite Schistosoma mansoni directly in the aquatic environment, where the nonhuman part of the parasite life cycle occurs. This is a report of the successful detection of S. mansoni in freshwater samples by using aquatic eDNA. True eDNA was detected in as few as 10 cercariae per liter of water in laboratory experiments. The field applicability of the method was tested at known transmission sites in Kenya, where comparison of schistosome detection by conventional snail surveys (snail collection and cercariae shedding) with eDNA (water samples) showed 71% agreement between the methods. The eDNA method furthermore detected schistosome presence at two additional sites where snail shedding failed, demonstrating a higher sensitivity of eDNA sampling. We conclude that eDNA provides a promising tool to substantially improve the environmental surveillance of S. mansoni Given the proper method and guideline development, eDNA could become an essential future component of the schistosomiasis control tool box needed to achieve the goal of elimination.

Infection with Batrachochytrium dendrobatidis is common in tropical lowland habitats: Implications for amphibian conservation.

Numerous species of amphibians declined in Central America during the 1980s and 1990s. These declines mostly affected highland stream amphibians and have been primarily linked to chytridiomycosis, a deadly disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Since then, the majority of field studies on Bd in the Tropics have been conducted in midland and highland environments (>800 m) mainly because the environmental conditions of mountain ranges match the range of ideal abiotic conditions for Bd in the laboratory. This unbalanced sampling has led researchers to largely overlook host–pathogen dynamics in lowlands, where other amphibian species declined during the same period. We conducted a survey testing for Bd in 47 species (n = 348) in four lowland sites in Costa Rica to identify local host–pathogen dynamics and to describe the abiotic environment of these sites. We detected Bd in three sampling sites and 70% of the surveyed species. We found evidence that lowland study sites exhibit enzootic dynamics with low infection intensity and moderate to high prevalence (55% overall prevalence). Additionally, we found evidence that every study site represents an independent climatic zone, where local climatic differences may explain variations in Bd disease dynamics. We recommend more detection surveys across lowlands and other sites that have been historically considered unsuitable for Bd occurrence. These data can be used to identify sites for potential disease outbreaks and amphibian rediscoveries.

Serological proteomic screening and evaluation of a recombinant egg antigen for the diagnosis of low-intensity Schistosoma mansoni infections in endemic area in Brazil.

BackgroundDespite decades of use of control programs, schistosomiasis remains a global public health problem. To further reduce prevalence and intensity of infection, or to achieve the goal of elimination in low-endemic areas, there needs to be better diagnostic tools to detect low-intensity infections in low-endemic areas in Brazil. The rationale for development of new diagnostic tools is that the current standard test Kato-Katz (KK) is not sensitive enough to detect low-intensity infections in low-endemic areas. In order to develop new diagnostic tools, we employed a proteomics approach to identify biomarkers associated with schistosome-specific immune responses in hopes of developing sensitive and specific new methods for immunodiagnosis.Methods and findingsImmunoproteomic analyses were performed on egg extracts of Schistosoma mansoni using pooled sera from infected or non-infected individuals from a low-endemic area of Brazil. Cross reactivity with other soil-transmitted helminths (STH) was determined using pooled sera from individuals uniquely infected with different helminths. Using this approach, we identified 23 targets recognized by schistosome acute and chronic sera samples. To identify immunoreactive targets that were likely glycan epitopes, we compared these targets to the immunoreactivity of spots treated with sodium metaperiodate oxidation of egg extract. This treatment yielded 12/23 spots maintaining immunoreactivity, suggesting that they were protein epitopes. From these 12 spots, 11 spots cross-reacted with sera from individuals infected with other STH and 10 spots cross-reacted with the negative control group. Spot number 5 was exclusively immunoreactive with sera from S. mansoni-infected groups in native and deglycosylated conditions and corresponds to Major Egg Antigen (MEA). We expressed MEA as a recombinant protein and showed a similar recognition pattern to that of the native protein via western blot. IgG-ELISA gave a sensitivity of 87.10% and specificity of 89.09% represented by area under the ROC curve of 0.95. IgG-ELISA performed better than the conventional KK (2 slides), identifying 56/64 cases harboring 1–10 eggs per gram of feces that were undiagnosed by KK parasitological technique.ConclusionsThe serological proteome approach was able to identify a new diagnostic candidate. The recombinant egg antigen provided good performance in IgG-ELISA to detect individuals with extreme low-intensity infections (1 egg per gram of feces). Therefore, the IgG-ELISA using this newly identified recombinant MEA can be a useful tool combined with other techniques in low-endemic areas to determine the true prevalence of schistosome infection that is underestimated by the KK method. Further, to overcome the complexity of ELISA in the field, a second generation of antibody-based rapid diagnostic tests (RDT) can be developed.

Diagnostic Value of SjR2 Gene in Colonic Tissue from Schistosoma Japonicum Infected Hosts.

BackgroundThe prevalence and intensity of schistosomiasis infection in China has decreased markedly in recent years. Therefore, more accurate methods are critically needed to ensure further control of low-intensity schistosomiasis infection. For chronic schistosomiasis patients, the detection of schistosome eggs in colorectal mucosa tissues is commonly used. This work aimed to explore differences in sensitivity of the Schistosoma japonicum (S. japonicum) retrotransposon (SjR2) gene in colon tissue from S. japonicum infected hosts and to develop an ideal method for genetic diagnosis of low-intensity schistosomiasis.Material/MethodsSerum and colon samples were collected from mice at different time points, either post-infection (PI) or post-treatment (PT). Colorectal biopsy specimens from outpatients with schistosomiasis were collected. All samples from mice and patients, including serum as well as colon tissue containing eggs and tissue containing no eggs, were examined using the polymerase chain reaction technique.ResultsThe results showed that the SjR2 gene could be detected in all colon tissue containing at least one egg, except for when the egg was completely degraded. The positive rate of gene detection in serum was low. The results from egg-free colon tissue from around the eggs were more consistent with the actual parasitism in vivo.ConclusionsThe results indicate that detection of the gene in colon tissue located within a 0.5 cm distance from the eggs would be a practical and ideal method for genetic diagnosis of schistosomiasis. After the colorectal biopsy, this method can be a sensitive assisted examination to the clinical diagnosis of low-intensity schistosomiasis infection.

Urinary circulating DNA and circulating antigen for diagnosis of schistosomiasis mansoni: a field study.

To evaluate three non-invasive assays for the diagnosis of schistosomiasis mansoni in an Egyptian village. Urine was collected for the detection of circulating cathodic antigen (CCA) and cell-free parasite DNA (cfpd) by Point-of-contact (POC)-cassette assay and PCR, respectively. These tests were compared to Kato-Katz (KK) faecal thick smear for detection of Schistosoma mansoni eggs. Disease prevalence by POC-CCA assay was 86%; by PCR it was 39% vs. 27% by KK. Compared to KK, the sensitivity of POC-CCA reached 100%, but its specificity was only 19.2% with 41% accuracy. Sensitivity of the PCR assay for cfpd was 55.56%, and specificity was 67.12% with 64% accuracy. A new end point was calculated for combined analysis of KK, POC-CCA assay and PCR. Sensitivity for the three tests was 52.94%, 90.2% and 76.47%; specificity was 100% for KK and PCR and 18.37% for POC-CCA. The accuracy calculated for the three tests at the end point was 76% for KK, 55% for POC-CCA assay and 88% for PCR. Conventional PCR assay for detection of cfpd provides a potential screening tool for intestinal schistosomiasis with reliable specificity, reasonable accuracy and affordable financial and technical cost.

Coccidian Prevalence and Intensity in Free-Ranging and Rehabilitating Wild Raptors

Coccidians infect the intestines and other organs in vertebrates, causing pathogenicity ranging from asymptomatic infections to death. However, knowledge about coccidian infections is lacking for most free-living raptor species. Gathering basic information on coccidian infection would allow a better understanding of the basic ecology of raptors and would improve conservation actions. In this study, we assessed the prevalence and parasitic loads of coccidians in several free-ranging and rehabilitating wild raptor species in recovery centres in Spain and Belgium from 2015 to 2017. Faecal samples from 129 individuals of 17 different raptor species were collected. Coccidian oocysts were found in nine species. Significant differences were found in the prevalence of coccidians between the two countries, with higher rates in Belgium (45.0%) than in Spain (20.2%), as well as between age categories, with nestlings and juveniles showing a higher prevalence (30.5%) than adults (11.4%). Three different coccidian genera were identified. Caryospora spp. and Eimeria spp. were found in diurnal raptors and owls with medium/high loads (median ranging from 75-91344 ooc/g), while Isospora spp. was found only in Griffon Gyps fulvus and Egyptian Vultures Neophron percnopterus at low infection intensities (62-170 ooc/g). We present the first case of Isospora spp. in European vultures, although it is unclear if this is a true intestinal parasitisation or a pseudo-parasitisation with oocysts from livestock on which the vultures fed. Despite the limited sample size in our study, our results contribute to filling a gap in the knowledge of coccidian infections in wild birds.—Crespo-Gines, R., Lopez, D.S, Berriatua, E., Blanco, G., Candela, M.G. & Perez-Garcia, J.M. (2019). Coccidian prevalence and intensity in free-ranging and rehabilitating wild raptors. Ardeola, 66: 65-76.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations.

Comparison of stool examination techniques to detect Opisthorchis viverrini in low intensity infection

Opisthorchiasis, caused by Opisthorchis viverrini, remains the public health significance in Thailand, particularly in the northeastern region. Number of parasitological techniques is available for diagnosis. However, the detection the parasite’s eggs in stool still referred as gold standard. Today, most people living in the endemic areas harbored the light infection. In this study, we compared the performance of formalin-ethyl acetate concentration technique (FECT), Kato-Katz technique, fecal parasite concentrator kit (FPCK) and direct simple smear technique for O. viverrini egg examination in stool. The results revealed that the FECT gave the best sensitivity (91.0%) followed by Kato-Katz technique, FPCK and direct simple smear techniques. Interestingly, the FECT showed the highest sensitivity in both groups of egg per gram (EPG) <50 (94.3%) and EPG ≥ 50 (100%). The FPCK and direct simple smear technique exhibited the higher sensitivity in EPG ≥ 50 group compared with EPG < 50 group (p < 0.05). However, the sensitivity of FPCK was not statistically differed from that direct simple smear in EPG <50 and EPG ≥50 group. In conclusion, the FECT showed the highest efficiency to detect O. viverrini egg in stool, followed by Kato-Katz technique, FPCK and direct simple smear technique. Substituting FPCK (Mini Parasep® Kit) for FECT and Kato-Katz method is not recommended for low intensity infection.

Investigations on the distribution of Schistosoma turkestanicum Skrjabin, 1913 (Trematoda: Schistosomatidae) infection of red deer in Hungary and a combined method for the detection of S. turkestanicum eggs in droppings

Additional geographical distribution of the Central European populations of Schistosoma turkestanicum and the detectability of their eggs in droppings were investigated in red deer samples, because this rare species had previously been shown only in a single Hungarian habitat. Samples from visceral organs, intestinal contents, and droppings on the ground from 11 hunting areas of Hungary were investigated to find a new presence of this fluke. Close to the first site of detection in the Gemenc forest another habitat along the southern border of the country was found where the parasite lives in red deer. Therefore, it is possible that the worm also occurs in neighbouring Serbia or Croatia. Schistosoma turkestanicum causes a low-intensity infection in red deer and this host sheds low amounts of eggs, therefore the eggs are difficult to detect. Droppings were cleared by sedimentation, filtered by sieve screening and then the eggs were flotated using solutions with an increasing density of 1200 g/L, 1300 g/L, 1350 g/L, and 1400 g/L while they were being stained red with acid fuchsin. Eggs in fresh faeces can be most efficiently separated from plant fibres using a flotation solution of 1350 g/L density, but in some cases eggs in old dung can be detected using a solution of a specific gravity lower or higher than that. By combining the advantages of the three concentration processes, eggs of S. turkestanicum, which are more recognisable by the red stain, can be found in samples in which they are present at a density lower than 1/g.

Diagnosis of feline whipworm infection using a coproantigen ELISA and the prevalence in feral cats in southern Florida.

Trichuris felis, the whipworm of cats, is a relatively rare parasite, although more common in tropical and sub-tropical regions such as the Caribbean and South America. In southern Florida, T. felis is known to occur, but estimating prevalence can be challenging using fecal egg counts due to low intensity and single sex infections. A microplate enzyme-linked immunosorbent assays (ELISAs) for parasite-specific antigen in feces could increase the ability to detect these infections. In this study, the IDEXX Fecal Dx™ antigen ELISA for whipworm (designed for detection of Trichuris vulpis) was evaluated for detection of T. felis using 35 feral cats from St. Kitts, euthanized for non-study related reasons. Twenty-nine of the cats were positive for T. felis with worm counts ranging from 1 to 66 per cat (mean 9.6) and egg counts ranging from 0 to >500 (mean 109.8). The ELISA detected 26 of 29 positive cats while flotation (centrifugation with Sheather's sugar solution) detected 24 of the 29 positive cats. To estimate prevalence in southern Florida, feces from 65 feral cats from the greater Miami area were tested using the ELISA and fecal flotation (centrifugation with zinc sulfate). Twenty-five cats (38%) were identified as positive with the ELISA compared to 17 using fecal flotation. This prevalence was surprising and further investigated by reviewing results of feline samples from Florida submitted to IDEXX Reference Laboratories between 2010 and 2017 and analyzed using fecal flotation. While prevalence was below 1%, there was an apparent trend in increasing prevalence. The results of this study confirm that the IDEXX Fecal Dx™ antigen test for whipworm ELISA, while developed for T. vulpis, can detect T. felis infections. It also suggests that prevalence might be higher than previously known in Florida and might be increasing. Further studies are required to determine the distribution of this higher prevalence and if the distribution and prevalence of T. felis are changing.

Non-native parasitic copepod Neoergasilus japonicus (Harada, 1930) utilizes non-native fish host Lepomis gibbosus (L.) in the floodplain of the River Dyje (Danube basin).

The parasitic copepod Neoergasilus japonicus (Harada, 1930) (Ergasilidae), native to east Asia, is widely distributed in Asia, Europe, and North and Central America. Recently, this species appeared in lentic water bodies of the River Dyje floodplain (Danube basin, Czech Republic). It was first recorded in 2015 and in 2years it reached a 100% prevalence in recently expanding non-native fish host, Lepomis gibbosus (Linnaeus, 1758) (Centrarchidae, native to North America) at two borrow pits. Abundance of N. japonicus increased with fish length, with maximum intensity of infection reaching 99 parasites per fish. The parasite was most frequently found attached to the dorsal and anal fins of fish, while preference for the dorsal fin was more evident with lower infection intensities. Utilization of expanding fish hosts in water bodies that are regularly interconnected via natural or managed flooding may support the rapid dispersal of this non-native parasite.

The Impact of Intensive Versus Standard Anthelminthic Treatment on Allergy-related Outcomes, Helminth Infection Intensity, and Helminth-related Morbidity in Lake Victoria Fishing Communities, Uganda: Results From the LaVIISWA Cluster-randomized Trial.

BackgroundThe prevalence of allergy-related diseases is increasing in low-income countries. Parasitic helminths, common in these settings, may be protective. We hypothesized that intensive, community-wide, anthelminthic mass drug administration (MDA) would increase allergy-related diseases, while reducing helminth-related morbidity.MethodsIn an open, cluster-randomized trial (ISRCTN47196031), we randomized 26 high-schistosomiasis-transmission fishing villages in Lake Victoria, Uganda, in a 1:1 ratio to receive community-wide intensive (quarterly single-dose praziquantel plus albendazole daily for 3 days) or standard (annual praziquantel plus 6 monthly single-dose albendazole) MDA. Primary outcomes were recent wheezing, skin prick test positivity (SPT), and allergen-specific immunoglobulin E (asIgE) after 3 years of intervention. Secondary outcomes included helminths, haemoglobin, and hepatosplenomegaly.ResultsThe outcome survey comprised 3350 individuals. Intensive MDA had no effect on wheezing (risk ratio [RR] 1.11, 95% confidence interval [CI] 0.64–1.93), SPT (RR 1.10, 95% CI 0.85–1.42), or asIgE (RR 0.96, 95% CI 0.82–1.12). Intensive MDA reduced Schistosoma mansoni infection intensity: the prevalence from Kato Katz examinations of single stool samples from each patient was 23% versus 39% (RR 0.70, 95% CI 0.55–0.88), but the urine circulating cathodic antigen test remained positive in 85% participants in both trial arms. Hookworm prevalence was 8% versus 11% (RR 0.55, 95% CI 0.31–1.00). There were no differences in anemia or hepatospenomegaly between trial arms.ConclusionsDespite reductions in S. mansoni intensity and hookworm prevalence, intensive MDA had no effect on atopy, allergy-related diseases, or helminth-related pathology. This could be due to sustained low-intensity infections; thus, a causal link between helminths and allergy outcomes cannot be discounted. Intensive community-based MDA has a limited impact in high-schistosomiasis-transmission fishing communities, in the absence of other interventions.Clinical Trials RegistrationISRCTN47196031.