Low-intensity Infections Research Articles

Optimizing moxidectin dosing for Strongyloides stercoralis infections: Insights from pharmacometric modeling.

Moxidectin is a frontrunner drug candidate in the treatment of strongyloidiasis. A dose of 8 mg is recommended to treat this indication, which shows a reasonably good efficacy and tolerability profile. Yet, owing to the unique life cycle of Strongyloides stercoralis (S. stercoralis) that entails internal autoinfection, a curative treatment would be desirable. Population‐based pharmacometric modeling that would help to identify an ideal dosing strategy are yet lacking. The aims of this study were to (i) explore the exposure‐efficacy response relationship of moxidectin in treating S. stercoralis and (ii) evaluate whether moxidectin treatment outcomes in terms of cure rates at baseline as compared to post‐treatment could be optimized. Our pharmacodynamic model suggests high predictive power (area under the concentration time curve‐receiver operating characteristic [AUC‐ROC] 0.817) in the probability of being cured by linking an exposure metric (i.e., AUC0‐24 or maximum concentration [Cmax]) to baseline infection intensity. Pharmacometric simulations indicate that with a minimum dose of 4 mg a maximum cure rate of ~ 95% is established in the low infection intensity group (larvae per gram [LPG] ≥0.4–1), whereas in the moderate‐to‐high intensity group (LPG >1) the cure rate plateaus at ~ 87%, following an 8 mg dose. To enhance efficacy further, studies using repeated dosing based on the duration of the autoinfection cycle, for example a two‐dose regimen 3 weeks apart should be considered. Simulations revealed similar Cmax in both treatment courses of a two‐dose regimen; hence safety should not be a concern. Collectively, our results provide evidence‐based guidance for enhanced dosing strategies and should be considered when designing future treatment strategies.

Parasitic helminth fauna of tree frogs from cocoa plantations at Ugboke, Edo State, Nigeria

Cocoa pods are vulnerable to pest and diseases which often cause huge financial losses to farmers. To address this challenge and improve yield, cocoa farmers often resort to pesticide application on the cocoa trees. This leads to deposition of pesticides residues on the cocoa trees, the undergrowth and plantations floor with devastating consequences for amphibians including tree frogs. Previous studies have reported the immune suppressive nature of pesticides on anurans thereby rendering them more susceptible to infection. This study is part of an on-going investigation of the effect of pesticide application on the pattern of helminth parasitic infections of anurans in pesticide-treated cocoa plantations at Ugboke, Edo State. A total of 354 tree frogs belonging to three genera (Leptopelis, Hyperolius and Afrixalus), consisting of 14 species were examined. A high species richness (d=1.971) and diversity (H’=2.215) was recorded. Ten species (71.43%) of these frogs were infected while four (28.57%) were uninfected. The overall prevalence of parasitic infections was 30.23%. Thirteen helminth parasites including three cestodes, two digeneans and eight nematode species were recovered. A significantly higher (P<0.05) prevalence of infection was recorded during the wet season (31.64%) than in the dry (10.53%). There was high parasite diversity with low prevalence and infection intensity of infection as previously reported for other anurans collected from the same cocoa plantations

FLOTAC Technique for Soil-Transmitted Helminth Infection Diagnosis

Human helmintiasis is a neglected disease with significant economic impacts caused by its effects on performance and cognition. The burden of many helminth infections is not well understood due to the lack of progress in detecting low-intensity infection in elimination programs. Furthermore, the decision for individual and community treatments, as well as the community-based control program evaluation, obviously depends on the technics used for parasitological diagnostic. A well-established diagnostic technic will be beneficial to detect and eliminate the disease. Therefore, this study aimed to compare the performance of FLOTAC and FECT technics for detecting helminth infections in human stool. A total of 149 fecal specimens were collected from schoolchildren in Nangapanda village, Ende District, East Nusa Tenggara Province in 2012. The sensitivity of both technics was analyzed using the kappa analysis. Positive results from both technics were used as the gold standard. The sensitivity of FLOTAC for diagnosing T. Trichiura, A. lumbricoides and hookworm infections were 100%, 100%, and 82%, respectively, while the sensitivity of FECT was 80%, 7%, and 18%, respectively. FLOTAC yielded considerably higher mean faecal egg counts (11,452, 1,038, and 19 eggs per gram stool (EPG) for A. lumbricoides, T. Trichiura , and hookworm). FLOTAC technique was considerably more sensitive than FECT in diagnosing soil-transmitted helminth infections. In conclusion, FLOTAC can be used as a diagnosis tool for future helminth control programs.

Soil-transmitted helminth infections after mass drug administration for lymphatic filariasis in rural southern India.

Targeted deworming is the current strategy for control of morbidity associated with soil-transmitted helminths (STH) among at-risk populations: preschool-aged children, school-aged children and women of childbearing age. We report the prevalence and intensity of STH in a district after lymphatic filariasis (LF) mass drug administration (MDA) in southern India where albendazole was co-administered from 2001. Children aged 2 to 15years and adults (defined as ≥15years) in a rural administrative block of Tamil Nadu were recruited using a probability proportional to size method. Stool samples were screened and eggs per gram (EPG) determined by Kato-Katz method. Multilevel logistic regression (MLR) and multilevel negative binomial regression (MNBR) analyses were used to identify factors associated with infection and intensity, respectively. Of 862 participants who provided samples, 60 (7.0%; 95% confidence interval (CI): 5.3-8.7) were positive for STH with a predominance of hookworm infections (n= 57, 6.6%; 95% CI: 5.0-8.3). Increasing age (odds ratio (OR): 1.09; 95% CI: 1.04-1.15) and regular usage of the toilet (OR: 0.32; 95% CI: 0.12-0.88) were independently associated with hookworm infection and age was significantly associated with increasing intensity of hookworm infection (infection intensity ratio (IIR): 1.28; 95% CI: 1.19-1.37). A brief review of STH prevalence in endemic settings before and after the stoppage of LF MDA indicated that, in most settings, a substantial reduction in STH prevalence is seen. Community-wide MDA in all age groups in these post-LF MDA districts with low prevalence and light intensity infections could result in transmission interruption of STH.

Prevalence, intensity and associated risk factors of Schistosoma mansoni infections among schoolchildren around Lake Tana, northwestern Ethiopia.

Schistosomiasis is one of the widely distributed neglected tropical diseases. It is a serious public health problem in sub-Saharan Africa. The disease is highly prevalent and widely distributed in Ethiopia due to suitable environmental factors and human activities. The prevalence and infection intensity varied from locality to locality in the country. This study aimed to assess the prevalence and intensity of S. mansoni infection and associated risk factors among schoolchildren around Lake Tana. A school-based cross-sectional study was conducted among 710 schoolchildren from February to April 2021 in eight selected primary schools around Lake Tana. A questionnaire was used to collect data on socio-demographic information and potential risk factors of S. mansoni infection. After collecting socio-demographic information, students were requested to bring about 2grams of stool specimens for parasitological examination. The collected stool samples were processed using a single Kato-Katz and Ritchie's concentration techniques. The data were analyzed using SPSS software version 23 and factors with a p-value < 0.05 were considered as statistically significant. The overall prevalence of S. mansoni was 34.9% (95% CI: 31.4-38.7) among schoolchildren in the study area. The eggs per gram (EPG) of stool ranged from 24 to 1659 with arithmetic and geometric mean values of 138.1 EPG and 85.1 EPG, respectively. The majority of S. mansoni infections (61.4%) were classified as low infection intensity. Among the different determinant factors being male (AOR = 1.74; 95%CI = 1.233-2.457; P-value = 0.002), bathing habits (AOR = 1.494; 95%CI = 1.013-2.199; P-value = 0.043) and students attending at Qunzela primary school (AOR = 10.545; 95%CI = 3.264-34.067; P-value = 0.001), Alabo primary school (AOR = 3.386; 95%CI = 1.084-10.572; P-value = 0.036) were significantly associated with S. mansoni infection. This study revealed that more than one-third of schoolchildren were infected by S. mansoni in the study area. The majority of the infections were classified as low infection intensity. Being male, bathing habits and schools in which students attended were independent explanatory factors for S. mansoni infection. Therefore, integrated control strategies are needed to improve the health conditions of schoolchildren in the study area.

Implementation of a Vaccination Program Based on Epidemic Geospatial Attributes: COVID-19 Pandemic in Ohio as a Case Study and Proof of Concept

Geospatial vaccine uptake is a critical factor in designing strategies that maximize the population-level impact of a vaccination program. This study uses an innovative spatiotemporal model to assess the impact of vaccination distribution strategies based on disease geospatial attributes and population-level risk assessment. For proof of concept, we adapted a spatially explicit COVID-19 model to investigate a hypothetical geospatial targeting of COVID-19 vaccine rollout in Ohio, United States, at the early phase of COVID-19 pandemic. The population-level deterministic compartmental model, incorporating spatial-geographic components at the county level, was formulated using a set of differential equations stratifying the population according to vaccination status and disease epidemiological characteristics. Three different hypothetical scenarios focusing on geographical subpopulation targeting (areas with high versus low infection intensity) were investigated. Our results suggest that a vaccine program that distributes vaccines equally across the entire state effectively averts infections and hospitalizations (2954 and 165 cases, respectively). However, in a context with equitable vaccine allocation, the number of COVID-19 cases in high infection intensity areas will remain high; the cumulative number of cases remained >30,000 cases. A vaccine program that initially targets high infection intensity areas has the most significant impact in reducing new COVID-19 cases and infection-related hospitalizations (3756 and 213 infections, respectively). Our approach demonstrates the importance of factoring geospatial attributes to the design and implementation of vaccination programs in a context with limited resources during the early stage of the vaccine rollout.

Towards soil-transmitted helminths transmission interruption: The impact of diagnostic tools on infection prediction in a low intensity setting in Southern Mozambique.

World Health Organization goals against soil-transmitted helminthiases (STH) are pointing towards seeking their elimination as a public health problem: reducing to less than 2% the proportion of moderate and heavy infections. Some regions are reaching WHO goals, but transmission could rebound if strategies are discontinued without an epidemiological evaluation. For that, sensitive diagnostic methods to detect low intensity infections and localization of ongoing transmission are crucial. In this work, we estimated and compared the STH infection as obtained by different diagnostic methods in a low intensity setting. We conducted a cross-sectional study enrolling 792 participants from a district in Mozambique. Two stool samples from two consecutive days were collected from each participant. Samples were analysed by Telemann, Kato-Katz and qPCR for STH detection. We evaluated diagnostic sensitivity using a composite reference standard. By geostatistical methods, we estimated neighbourhood prevalence of at least one STH infection for each diagnostic method. We used environmental, demographical and socioeconomical indicators to account for any existing spatial heterogeneity in infection. qPCR was the most sensitive technique compared to composite reference standard: 92% (CI: 83%- 97%) for A. lumbricoides, 95% (CI: 88%- 98%) for T. trichiura and 95% (CI: 91%- 97%) for hookworm. qPCR also estimated the highest neighbourhood prevalences for at least one STH infection in a low intensity setting. While 10% of the neighbourhoods showed a prevalence above 20% when estimating with single Kato-Katz from one stool and Telemann from one stool, 86% of the neighbourhoods had a prevalence above 20% when estimating with qPCR. In low intensity settings, STH estimated prevalence of infection may be underestimated if based on Kato-Katz. qPCR diagnosis outperformed the microscopy methods. Thus, implementation of qPCR based predictive maps at STH control and elimination programmes would disclose hidden transmission and facilitate targeted interventions for transmission interruption.

QUANTIFYING BILATERAL INFECTION PATTERNS IN THE TREMATODE ALLOGLOSSIDIUM RENALE.

Within-host distributions of parasites can have relevance to parasite competition, parasite mating, transmission, and host health. We examined the within-host distribution of the adult trematode Alloglossidium renale infecting the paired antennal glands of grass shrimp. There are 4 possible parasite distributions for infections of paired organs: random, uniform, biased aggregation to 1 particular organ (e.g., left vs. right), or inconsistently biased (aggregated, but does not favor 1 side). Previous work has shown that morphological asymmetries in hosts can lead to biased infections of paired organs. Apparent symmetry between the antennal glands of grass shrimp leads to the prediction that there would be no bias for 1 particular organ. However, an alternative prediction stems from the fact that A. renale is hermaphroditic: aggregation between glands would increase outcrossing opportunities and thus, avoid inbreeding via self-mating. Existing methods to test for an overall pattern did not apply to the A. renale system because of low-intensity infections as well as many 0 values for abundance per unit of the antennal gland. Hence, we used Monte Carlo simulations to determine if the observed overall patterns differed from those expected by randomly allocating parasites into groups of 2. We found that in 3 of 4 data sets, A. renale infections did not deviate from random distributions. The fourth data set had a more uniform pattern than expected by chance. As there was no aggregation between glands and the proportion of worms in single gland infections did not differ from that expected by chance alone, we found no evidence of inbreeding avoidance as might be manifested via a within-host distribution. Given the large proportion of worms in single infections, we predict as a major evolutionary outcome that populations of A. renale will be largely inbred.

Expanding known global biodiversity of Yamaguticestus (Cestoda: Phyllobothriidea) parasitizing catsharks (Pentanchidae and Scyliorhinidae)

This paper aimed to test the prediction that substantial undiscovered biodiversity in the tapeworm genus Yamaguticestus Caira, Bueno & Jensen, 2021 exists in the 16 of 18 genera of catsharks globally that have not yet been examined for tapeworms. A total of 200 catsharks of 10 species representing eight genera were sampled opportunistically from the waters off Australia, Chile, Malaysian Borneo, South Africa, South Korea, and the UK between 1991 and 2017. Six species in four genera (i.e., Apristurus Garman, Asymbolus Whitley, Holohalaelurus Fowler, and Scyliorhinus Blainville) were found to host a total of six new species of Yamaguticestus, tripling the number of described species. The new species are Yamaguticestus africanae sp. nov. from Scyliorhinus capensis, Yamaguticestus ellisi sp. nov. from Scyliorhinus canicula, Scyliorhinus fairweatherae sp. nov. from Holohalaelurus regani, Yamaguticestus kihongkimi sp. nov. from Scyliorhinus torazame, and Yamaguticestus kuchtai sp. nov. from Apristurus aphyodes. The new species were characterized using a combination of light and scanning electron microscopy; sequence data for the D1–D3 region of the 28S rRNA gene were generated for five of the species. Transfer of a species formerly assigned to Calyptrobothrium Monticelli, 1893 that is morphologically consistent with Yamaguticestus added Cephaloscyllium Gill to the list of catshark genera known to host this genus. Most tapeworm species exhibited a remarkably low prevalence and intensity of infection suggesting that our failure to detect infection in the four genera of sharks represented by small sample sizes may not be indicative of their unsuitability as hosts. Our results suggest that the earlier prediction that 70 species of Yamaguticestus remain to be discovered in catsharks across the planet may actually be an underestimate. http://zoobank.org/urn:lsid:zoobank.org:pub:63F48CF6-ED06-44FC-839D-

Ecological Scenarios and Parasite Diversity in Anurans of West Africa: A Review

This paper is a survey of the parasite diversity, prevalence and infection intensity in anurans in diverse ecological settings in West Africa. The settings included natural habitats (rainforests, freshwater creeks, Guinea and Sudan savannas), monoculture plantations (cocoa, cotton and oil palm), urbanized and urbanizing rainforest biotopes and polluted environments due to oil industry activities. The natural habitats had higher amphibian species diversity, moderate parasite prevalence and low infection intensity, showing a balance in the host/parasite relationship. These habitats yielded most of the monogeneans, among which were new species. The freshwater creek biotope had low amphibian diversity, but hosts from this environment harbored several parasite taxa, a situation attributed to a prolonged wet season, high environmental humidity and persistent breeding pools for insect vectors in this area. The monoculture plantations were characterized by high parasite prevalence but lower infection intensity. For example, in the Pendjari Biosphere Reserve in Bénin Republic, the Agricultural Zone (AZ) had higher parasite prevalence values, while the National Park (NP) and Buffer Zone (BZ) had higher infection intensities. Higher prevalence was attributed to the single or combined effects of vector population explosion, immune-suppression by agrochemicals, nutrient enrichment and eutrophication from fertilizer use. The lower infection intensity was attributed to the inhibitory effect of the pesticide-contaminated environment on the free-living larval stages of parasites. The adverse effect of pesticide contamination was also evident in the lower infection intensity recorded in the anurans from the cocoa plantations at Ugboke in comparison to those from the pesticide-free village settlement. Urbanization reduced host diversity and numbers and increased the vector population, resulting in unusually high parasite prevalence and infection intensities at Diobu and Port Harcourt and high prevalence recorded for Ophidascaris larvae in the anurans of Evbuabogun. Oil pollution in the mangrove community reduced both host and parasite diversity; infection intensity was also low due to the adverse conditions confronting free-living stages of parasites in their development milieu. The high prevalence values obtained for monogeneans (Polystoma spp.) in Ptychadena spp. from Ogoniland was presumed to have resulted from host tadpole sequestration and exposure to high oncomiracidia burden in the few hospitable ponds. Also reviewed is the phenomenon of amphibian paratenism, a strategy on which many helminth parasites rely on for their trophic transmission to their definitive hosts.

Epidemiology of soil-transmitted helminths following sustained implementation of routine preventive chemotherapy: Demographics and baseline results of a cluster randomised trial in southern Malawi.

Malawi has successfully leveraged multiple delivery platforms to scale-up and sustain the implementation of preventive chemotherapy (PCT) for the control of morbidity caused by soil-transmitted helminths (STH). Sentinel monitoring demonstrates this strategy has been successful in reducing STH infection in school-age children, although our understanding of the contemporary epidemiological profile of STH across the broader community remains limited. As part of a multi-site trial evaluating the feasibility of interrupting STH transmission across three countries, this study aimed to describe the baseline demographics and the prevalence, intensity and associated risk factors of STH infection in Mangochi district, southern Malawi. Between October-December 2017, a community census was conducted across the catchment area of seven primary healthcare facilities, enumerating 131,074 individuals across 124 villages. A cross-sectional parasitological survey was then conducted between March-May 2018 in the censused area as a baseline for a cluster randomised trial. An age-stratified random sample of 6,102 individuals were assessed for helminthiasis by Kato-Katz and completed a detailed risk-factor questionnaire. The age-cluster weighted prevalence of any STH infection was 7.8% (95% C.I. 7.0%-8.6%) comprised predominantly of hookworm species and of entirely low-intensity infections. The presence and intensity of infection was significantly higher in men and in adults. Infection was negatively associated with risk factors that included increasing levels of relative household wealth, higher education levels of any adult household member, current school attendance, or recent deworming. In this setting of relatively high coverage of sanitation facilities, there was no association between hookworm and reported access to sanitation, handwashing facilities, or water facilities. These results describe a setting that has reduced the prevalence of STH to a very low level, and confirms many previously recognised risk-factors for infection. Expanding the delivery of anthelmintics to groups where STH infection persist could enable Malawi to move past the objective of elimination of morbidity, and towards the elimination of STH. Trial registration: NCT03014167.

Environmental Correlates of Prevalence of an Intraerythrocytic Apicomplexan Infecting Caribbean Damselfish

Parasites are an integral part of coral reef ecosystems due to their influences on population dynamics, biodiversity, community structure, and food web connectivity. The Phylum Apicomplexa contains ubiquitous animal associates including the causative agents of globally important human diseases such as malaria and cryptosporidiosis. Despite their ubiquity, little is known about the biology, ecology, or distribution of these microorganisms in natural animal populations. In the US Virgin Islands, the dusky damselfish (Stegastes adustus) had a high but variable incidence of a Haemohormidium-like blood apicomplexan among 30 sites sampled. Microscopic analyses of blood smears allowed us to group these fish as infected, having low intensity infections, or uninfected. Regression analyses detected no significant differences in the condition indices (expressed as length–mass ratio). However, infection was clearly associated with potentially extremely high leukocyte counts among infected S. adustus that were not seen in uninfected fish. These results suggested the potential for some impact on the host. Linear mixed effects models indicated that S. adustus population density and meridional flow velocity were the main predictors of apicomplexan prevalence, with presence of other Stegastes species, population distance from watershed, zonal flow velocity, the complexity of the surrounding habitat, and season not showing any significant relationship with fish infection.

Intestinal helminthic infection and allergic disorders among school children enrolled in mass deworming program, Sululta, Ethiopia

BackgroundIntestinal helminths have been proposed to have a protective role against allergic sensitization and atopic diseases. However, consistent data demonstrating this are lacking in Sub-Saharan countries. We aimed to assess the association between intestinal helminths and allergic disorders among school children enrolled in mass deworming program in Sululta, Ethiopia.MethodsA cross sectional study was conducted among 526 school children aged 5 to 14 years old from primary government schools in Sululta district, Ethiopia. An interviewer-led questionnaire administered to parents provided information on demographic and lifestyle variables. Questions on allergic disease symptoms were collected using the International Study of Asthma and Allergies in Children (ISAAC) questionnaire 6 months following deworming treatments. Atopy was defined as a positive skin prick test reaction to one or both dust mite (Dermatophagoides) and German cockroach (Blatella germanica) allergens. Fresh stool samples were collected, processed, and examined by direct wet mount, Kato-Katz technique, and formol-ether concentration technique. Multivariate logistic regressions were used to assess the association between allergic disorder and helminths infection.ResultsOf the total 526 school children, 58.2% were females. Overall, 24% (126/526) had allergic symptoms, 5.1% (27/526) had atopy, and 16.9% (89/526) had intestinal helminths. There was no association between helminthic infection and self-reported allergic symptoms (P = 0.317), but Ascaris lumbricoides infection was positively associated with atopy (AOR = 4.307, 95% CI 1.143–16.222, P = 0.031). Atopy was related to increased allergy symptoms (AOR = 2.787, 95% CI 1.253–6.197, P = 0.012), and family history of allergy was associated with increased childhood allergy (AOR = 2.753, 95% CI 1.565–4.841, P = 0.001). Deworming in the past 6 months showed a reduced odd of self-reported allergic symptoms (AOR = 0.581, 95% CI 0.366–0.954, P = 0.034).ConclusionWhile no significant association between self-reported allergy and helminths was found in this study, this may have been due to the low prevalence and intensity of helminthic infection in the sample. There was a positive association between Ascaris lumbricoides and atopy. To further examine the underlying mechanism behind this positive association, a longitudinal study is needed.

Potential of antibody test using Schistosoma mansoni recombinant serpin and RP26 to detect light-intensity infections in endemic areas.

Schistosomiasis remains a worldwide public health problem, especially in sub-Saharan Africa. The World Health Organization targets the goal for its elimination as a public health problem in the 2030 Neglected Tropical Diseases (NTDs) Roadmap. Concerted action and agile responses to challenges will be necessary to achieve the targets. Better diagnostic tests can accelerate progress towards the elimination by monitoring disease trends and evaluating the effectiveness of interventions; however, current examinations such as Kato-Katz technique are of limited power to detect light-intensity infections. The point-of-care circulating cathodic antigen (POC-CCA) test shows a higher sensitivity compared to the reference standard, Kato-Katz technique, but it still lacks sufficient sensitivity with low infection intensity. In this study, we examined antibody reactions against recombinant protein antigens; Schistosoma mansoni serine protease-inhibitor (SmSerpin) and RP26, by enzyme-linked immunosorbent assay (ELISA) in plasma samples with light-intensity infection. The sensitivity using the cocktail antigen of recombinant SmSerpin and RP26 showed 83.7%. The sensitivity using S. mansoni soluble egg antigen (SmSEA) was 90.8%, but it showed poor specificity (29.7%), while the cocktail antigen presented improved specificity (61.4%). We conclude that antibody detection to the SmSerpin and RP26 protein antigens is effective to detect S. mansoni light-intensity infections. Our study indicates the potential of detecting antibody against recombinant protein antigens to monitor the transmission of schistosomiasis in low endemicity contexts.

Exposure to nanoplastics affects the outcome of infectious disease in phytoplankton.

Infectious diseases of humans and wildlife are increasing globally but the contribution of novel artificial anthropogenic entities such as nano-sized plastics to disease dynamics remains unknown. Despite mounting evidence for the adverse effects of nanoplastics (NPs) on single organisms, it is unclear whether and how they affect the interaction between species and thereby lead to ecological harm. In order to incorporate the impact of NP pollution into host-parasite-environment interactions captured in the "disease triangle", we evaluated disease outcomes in the presence of polystyrene NP using an ecologically-relevant host-parasite system consisting of a common planktonic cyanobacterium and its fungal parasite. NP at high concentrations formed hetero-aggregates with phytoplankton and inhibited their growth. This coincided with a significant reduction in infection prevalence, highlighting the close interdependency of host and parasite fitness. Lower intensity of infection in the presence of NP indicates that reduced disease transmission results from the parasite's diminished ability to establish new infections as NP formed aggregates around phytoplankton cells. We propose that NP aggregation on the host's surface acts as a physical barrier to infection and, by reducing host light harvesting, may also hamper parasite chemotaxis. These results demonstrate that the consequences of NP pollution go well beyond toxic effects at the individual level and modulate the intensity of species interactions, thereby potentially eliciting diverse cascading effects on ecosystem functioning.

Spatial interactions between two nematode species along the intestine of the wood mouse Apodemus sylvaticus from woodland and grassland sites in southern England.

The distributions of the nematode parasites Heligmosomoides polygyrus and Syphacia stroma were quantified in three equal-length sections along the intestine of wood mice (Apodemus sylvaticus) trapped in three different locations in the south of England. The distribution of H. polygyrus did not change in the presence of S. stroma, this species being largely confined to the anterior third of the intestine, whether S. stroma was or was not present. However, while in single infections with S. stroma, worms were equally distributed in the anterior and middle sections of the intestine, in the presence of H. polygyrus, a higher percentage of worms was located in the middle section. This was a dose-dependent response by S. stroma to increasing worm burdens with H. polygyrus, and even relatively low intensities of infection with H. polygyrus (e.g. ≤10 worms) were sufficient to cause a posterior redistribution of S. stroma into the middle section. A similar posterior shift in the percentage distribution of S. stroma in the intestine was evident in juvenile and mature mice of both sexes, and in mice from all three study sites. The ecological significance of these results is discussed.

Soil-transmitted helminth infections among pre-school aged children in Gamo Gofa zone, Southern Ethiopia: Prevalence, intensity and intervention status

Soil-transmitted helminths (STH), i.e., Ascaris lumbricoides, Trichuris trichiura and hookworms are among the most prevalent Neglected Tropical Diseases (NTDs) in Ethiopia. Although pre-school aged children pay a high morbidity toll associated with STH infections, evidence on prevalence, intensity and intervention status is lacking in Ethiopia. This study, therefore, aimed to address these gaps to inform decision made on STH. We did a community-based cross-sectional study in five districts of Gamo Gofa zone, Southern Ethiopia; in January 2019. Data were collected using pre-tested questionnaire, and the Kato-Katz technique was used to diagnose parasites eggs in stool. Then, collected data were edited and entered into EpiData 4.4.2, and exported to SPSS software (IBM, version 25) for analysis. A total of 2462 PSAC participated in this study. Overall, the prevalence of STH was 23.5% (578/2462) (95% confidence interval (CI) = 21.8%-25.2%). As caris lumbricoides was the most prevalent (18.6%), followed by Trichuris trichiura (9.2%), and hookworms (3.1%). Of the total, 7.4% PSAC were infected with two STH species. Most of the positive cases with STH showed low infection intensities, while 15.1% ascariasis cases showed moderate infection intensities. The study found that 68.7% of PSAC were treated with albendazole. Also, household's level data showed that 39.4% used water from hand-dug well; 52.5% need to travel ≥30 minutes to collect water; 77.5% did not treat water, and 48.9% had no hand washing facility. In addition, almost 93% care givers achieved less than the mean knowledge and practice score (≤5) on STH prevention. This study showed that significant proportions of pre-school aged children are suffering from STH infections despite preventive chemotherapy exist at the study area. Also, gaps in the interventions against STH were highlighted. Thus, a call for action is demanding to eliminate STH among PSAC in Ethiopia by 2030.

The presence of Apicomplexan parasites in king scallops (Pecten maximus) in Scottish waters

The king scallop (Pecten maximus) is a commercially important species found around the United Kingdom coast. The association of an Apicomplexan-like parasite with mass mortality of Icelandic scallop (Chlamys islandica) in Iceland and the presence of identical parasites in king scallop (Pecten maximus) and queen scallop (Aequipecten opercularis) in Scotland raised serious concerns regarding the health of Scottish king scallops. Marine Scotland Science (MSS) conducted a survey in 2016 to assess the prevalence and the intensity of parasite infection in king scallops. King scallops were collected and sampled during the annual scallop dredge surveys in the Shetland Isles and the east and west coast of Scotland. The king scallop adductor muscle was macroscopically examined and tissue imprints taken to grade the intensity of infection. The parasite was present in the majority of the king scallops sampled in all surveyed areas: Shetland Isles 87.1%, east coast 76.0% and west coast of Scotland 64.1%. However, the parasitic infestations were light in intensity with the majority of the king scallops graded as 1 (≤20 zoites per microscopic field). No macroscopic changes in the adductor muscle were observed and histopathology examination revealed minor localized fiber degeneration of adjacent fibers to parasite clusters. The results suggested the parasite to be widespread around the Scottish coast and it appears to be able to live within the king scallop at low intensity of infection without causing significant downgrade of the adductor muscle (in terms of colour or texture) or mortality. The partial genome sequence of the parasite in king scallops from Scottish waters was identical to the one reported by Kristmundsson and Freeman (2018) in the Icelandic scallop in Icelandic waters.

Diagnostic comparison of stool exam and point-of-care circulating cathodic antigen (POC-CCA) test for schistosomiasis mansoni diagnosis in a high endemicity area in northeastern Brazil.

This study aimed to evaluate the performance of the point-of-care circulating cathodic antigen (POC-CCA) test in a highly endemic area in Brazil, comparing it to the Kato-Katz (KK) technique for sensitivity, specificity and the intensity of the reaction of the test in relation to the parasitic load. The community in Sergipe, Brazil, participated in the study, providing three stool samples, one of urine (POC-CCA) and fingers tick blood sample was tested by enzyme-linked immunosorbent assay (ELISA). Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, kappa coefficient and Spearman's correlation were calculated for the POC-CCA test using the KK as the reference. The prevalence of schistosomiasis by KK testing was 48.82%; POC-CCA (t+) 66.14%; POC-CCA (t-) 45.24%. ELISA results showed 100% agreement in individuals with high and moderate eggs per gram (EPG). POC-CCA presented good diagnostic performance in individuals with medium and high EPG, but there were a high number of false negatives in individuals with low intensity infections. As observed, POC-CCA-filter test improves accuracy and sensitivity compared to a conventional test.

First Histopathological Description of Parasites and Shell Conditions of the Donkey's Ear Abalone Haliotis asinina (Linnaeus, 1758) Cultured in Marine Cages and Land-Based Tanks in the Philippines

This study is the first attempt to assess parasitic infestations in grow-out cage culture and land-based grow-out tanks of the donkey's ear abalone Haliotis asinina in the Philippines. This histopathological study of the parasites was conducted from 2010 to 2013. Using 30 samples of abalones collected monthly from two sites, samples were measured and fixed in 10% formaldehyde in seawater, and routine histological techniques were used to identify the parasites. Water temperatures of the grow-out floating sea cages and the abalone hatchery facilities whose abalones were collected measured 27.5°C–32.5°C and 26°C–29°C, respectively; salinity in the area of the sea cages was 32–34 ppt, whereas salinity of the abalone hatchery was 32–35 ppt. Examination of the shell from cage-cultured abalones revealed the presence of burrowing polychaetes belonging to the families Serpulidae (prevalence, 32.5%) and Dorvilleidae (prevalence, 30%); on the other hand, only Dorvilleidae (prevalence of 28.5%) was detected in abalones from the hatchery. Histological examination revealed the presence of unknown ciliates (prevalence, 37.5%), Nematopsis sp. (prevalence, 17%), and metacestode Tylocephalum sp. (prevalence, 8.5%) from the grow-out cage-cultured abalones, whereas unidentified ciliates (prevalence, 32.5%) and Nematopsis sp. (prevalence, 10.5%) were detected from hatchery stock. The data collected showed that there was low-intensity infection and prevalence of parasites in abalones from grow-out cages and hatchery. These records of parasites constitute baseline information for future research work on abalones.