Malaria endemicity and co-infection with tissue-dwelling parasites in Sub-Saharan Africa: a review

Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood. In contrast, very little is known about such mechanisms in cases of malaria co-infections with tissue-dwelling parasites. This is lack of knowledge is exacerbated by misdiagnosis, lack of pathognomonic clinical signs and the chronic nature of tissue-dwelling helminthic infections. A good understanding of the implications of tissue-dwelling parasitic co-infections with malaria will contribute towards the improvement of the control and management of such co-infections in endemic areas. This review summarises and discusses current information available and gaps in research on malaria co-infection with gastro-intestinal helminths and tissue-dwelling parasites with emphasis on helminthic infections, in terms of the effects of migrating larval stages and intra and extracellular localisations of protozoan parasites and helminths in organs, tissues, and vascular and lymphatic circulations.

Soil-Transmitted Helminths and Associated Factors among Pre-School Children in Butajira Town, South-Central Ethiopia: A Community-Based Cross-Sectional Study

Background

Soil-transmitted helminths (STH) remain a major public health problem, particularly in tropical and sub-tropical regions of the world. Though infections are prevalent among all age groups, the world health organization (WHO) considers Pre-school age children (PSAC), school-aged children, and pregnant women as segments of population at high risk of STH morbidities.

Objective

This study aimed at determining the prevalence and infection intensity of STH and associated factors among PSAC in Butajira Town, south-central Ethiopia.

Methods

A community-based cross-sectional study was conducted from May to June, 2014 in Butajira Town. The PSAC were selected by systematic sampling technique and invited to participate in the present study. McMaster technique was employed for parasitological analysis of stool samples. Pearson’s Chi-square and Fisher’s exact tests were performed where appropriate to identify any association between STH infection and independent factors. Multivariate logistic regression model was fitted to identify independent predictors of STH among the PSAC. P-value less than 0.05 was considered statistically significant.

Results

A total of 377 (with 96% compliance rate) PSAC were able to provide complete data (socio-demographic information and stool sample). The study showed that 23.3% (88/377) PSAC were infected with one or more species of STH. Ascaris lumbricoides was the most prevalent STH (14.9%) followed by Trichuris trichiura (6.4%). The overall infection intensity, expressed as geometric mean for A. lumbricoides, T. trichiura, and hookworms were 229, 178, and 154 eggs per gram of stool, respectively. The multivariate logistic regression model estimated that being in the age group of 36–47 months (AOR: 2.5, 95% CI: 1.2–5.3, P = 0.016), untrimmed finger nail (AOR: 3.2, 95% CI: 1.8–5.5, P < 0.001), and not washing hands before a meal (AOR: 3.0, 95% CI: 1.7–5.4, P < 0.001) were independent predictors of STH infections among the children.

Conclusion

The present study showed that STH was a public health problem among PSAC in the study area necessitating annual deworming to control morbidities associated with STH. Besides, the existing health education program should also be strengthened to prevent re-infection.

The Right Tool for the Job: Detection of Soil-Transmitted Helminths in Areas Co-endemic for Other Helminths

Background

Due to the recent increased use of the McMaster (MM) fecal egg counting method for assessing benzimidazole drug efficacy for treating soil-transmitted helminth (STH) infections, the aim of the current study was to determine the operational value of including the MM method alongside the Kato-Katz (KK) fecal thick smear to increase the diagnostic sensitivity when STHs are co-endemic with trematode helminths (e.g., Schistosoma mansoni).

Methods

A cross-sectional study was conducted in school-aged children aged 4-18 years in the northeastern region of the State of Minas Gerais (Brazil), where Necator americanus, Ascaris lumbricoides, Trichuris trichiura, and S. mansoni are co-endemic. One fecal sample from each participant was collected and transported to the field laboratory for analysis. Coprological diagnosis was performed on each fecal sample by three different methods: Formalin-Ether Sedimentation (FES), KK and the MM technique. The diagnostic sensitivity and negative predictive value (NPV) of each technique was calculated using the combination of all three techniques as the composite standard. In order to determine the agreement between the three techniques Fleiss´ kappa was used. Both the Cure Rate (CR) and the Fecal Egg Count Reduction (FECR) were calculated using the two quantification techniques (i.e., the MM and KK).

Results

Fecal samples from 1260 children were analyzed. The KK had higher diagnostic sensitivity than the MM for the detection of both A. lumbricoides (KK 97.3%, MM 69.5%) and hookworm (KK 95.1%, MM 80.8%). The CR of a single dose of mebendazole varied significantly between the KK and MM for both A. lumbricoides (p = 0.016) and hookworm (p = 0.000), with lower rates obtained with the KK. On the other hand, the FECR was very similar between both techniques for both A. lumbricoides and hookworm.

Conclusion

The MM did not add any diagnostic value over the KK in areas where both STHs and trematodes were co-endemic. The lower sensitivity of the MM would have an important impact on the administration of selective school-based treatment in this area since if only the MM were used, 36 (13.9%) children diagnosed with A. lumbricoides would have gone untreated.

Diagnosis of intestinal helminths and Schistosoma mansoni infections is based on the detection of eggs in feces. There are many techniques available for both detection and quantification of infection. For the quantification of helminth infections, the methods traditionally used are the Kato-Katz (KK) fecal think smear in humans, and the McMaster (MM) counting method in animals. Recently, the MM has been used for assessing the efficacy of benzimidazole drugs for treating soil-transmitted helminth (STH) infections in humans. In most parts of the world, however, STHs occur simultaneously with other helminth species, and the MM does not detect other helminth eggs. Therefore, in this study we sought to determine if the use of the MM in an area of Brazil were both STHs and S. mansoni are co-endemic, added any value to the current standard of diagnosis using the KK.

Co-endemicity of Plasmodium falciparum and Intestinal Helminths Infection in School Age Children in Rural Communities of Kwara State Nigeria

Background

Malaria and intestinal helminths co-infection are major public health problems particularly among school age children in Nigeria. However the magnitude and possible interactions of these infections remain poorly understood. This study determined the prevalence, impact and possible interaction of Plasmodium falciparum and intestinal helminths co-infection among school children in rural communities of Kwara State, Nigeria.

Methods

Blood, urine and stool samples were collected from 1017 primary school pupils of ages 4–15 years. Stool samples were processed using both Kato-Katz and formol-ether concentration techniques and microscopically examined for intestinal helminths infection. Urine samples were analyzed using sedimentation method for Schistosoma haematobium. Plasmodium falciparum was confirmed by microscopy using thick and thin blood films methods and packed cell volume (PCV) was determined using hematocrit reader. Univariate analysis and chi-square statistical tests were used to analyze the data.

Results

Overall, 61.2% of all school children had at least an infection of either P. falciparum, S. haematobium, or intestinal helminth. S. haematobium accounted for the largest proportion (44.4%) of a single infection followed by P. falciparum (20.6%). The prevalence of malaria and helminth co-infection in the study was 14.4%. Four species of intestinal helminths were recovered from the stool samples and these were hookworm (22.5%), Hymenolepis species (9.8%), Schistosoma mansoni (2.9%) and Enterobius vermicularis (0.6%). The mean densities of P. falciparum in children co-infected with S. haematobium and hookworm were higher compared to those infected with P. falciparum only though not statistically significant (p = 0.062). The age distribution of both S. haematobium (p = 0.049) and hookworm (p = 0.034) infected children were statistically significant with the older age group (10–15 years) recording the highest prevalence of 47.2% and 25% respectively. Children who were infected with S. haematobium (RR = 1.3) and hookworm (RR = 1.4) have equal chances of being infected with P. falciparum as children with no worm infection. On the other hand children infected with Hymenolepis spp. (p<0.0001) are more likely to be infected with P. falciparum than Hymenolepis spp. uninfected children (RR = 2.0)

Conclusions

These findings suggest that multiple parasitic infections are common in school age children in rural communities of Kwara State Nigeria. The Hymenolepis spp. induced increase susceptibility to P. falciparum could have important consequences on how concurrent infections affect the expression or pathogenesis of these infections.

Malaria, schistosomiasis and intestinal helminths are parasitic diseases responsible for high morbidity and mortality in most tropical areas of the world. These parasitic diseases are common in Nigeria where people are co-infected with more than one parasite. This study investigate the prevalence and impact of these parasite co-infections in school age children in rural communities of Kwara State Nigeria. The result shows that over 61.0% of the school children had at least an infection of either P. falciparum, S. haematobium, or intestinal helminths with S. haematobium and P. falciparum accounting for the largest proportion of a single infection with 44.4% and 20.6% respectively. Children who were infected with S. haematobium (RR = 1.3) and hookworm (RR = 1.4) have equal chances of being infected with P. falciparum as children when compared with children with no infection. On the other hand children infected with Hymenolepis spp. (p<0.0001) have a higher chance of being infected with P. falciparum when compared to uninfected children (RR = 2.0). These findings suggest that Hymenolepis spp. may be associated with increase susceptibility to P. falciparum in this population of Nigeria children.

Suppressive functions of B cells in infectious diseases

B lymphocytes are often essential to successfully control invading pathogens and play a primary role in the protection afforded by successful vaccines through the production of specific antibodies. However, recent studies have highlighted the complex roles of B cells in infectious diseases, showing unexpectedly that some activated B cells limited host defense towards pathogens. This B-cell function involves production of regulatory cytokines including IL-10 and IL-35 and is reminiscent of the regulatory functions of B cells initially defined in autoimmune diseases. It is now known that various types of microbes including bacteria, helminths and viruses can induce IL-10-expressing B cells with inhibitory functions, indicating that this response is a general component of anti-microbial immunity. Interestingly, IL-10-producing B cells induced in the course of some microbial infections can inhibit concurrent immune responses directed towards unrelated antigens in a bystander manner and as a consequence ameliorate the course of autoimmune or allergic diseases. This could explain how some micro-organisms might provide protection from these pathologies, as formulated in the 'hygiene hypothesis'. In this review, we discuss the regulatory functions of B cells in bacterial, parasitic and viral infections, taking into account the phenotype of the B cells implicated, the signals controlling their induction and the cell types targeted by their suppressive activities.

Agreement of the Kato-Katz test established by the WHO with samples fixed with sodium acetate analyzed at 6 months to diagnose intestinal geohelminthes

The aim of this study was to evaluate the performance of the Kato-Katz test (WHO version) with stool samples from a rural area, fixed with sodium acetate (SAF). The Kato-Katz test was used to compare unfixed samples (conventional test) with the same samples containing SAF fixative at time 0 and at 6 months. The study included stools from 154 subjects. A marginally statistically significant decrease in prevalence was estimated only for hookworm, when comparing unfixed samples versus the SAF fixed samples read at 6 months (p=0.06). A significant reduction in parasite load was found for hookworm (p<0.01) and Trichuris trichiura (p<0.01) between the unfixed and the fixed sample read at 6 months, but not for Ascaris lumbricoides (p=0.10). This research suggests that the SAF fixative solution is a good option for transporting samples for diagnosis, especially in rural areas in developing countries.

Global feasibility assessment of interrupting the transmission of soil-transmitted helminths: a statistical modelling study

BACKGROUND

Emphasis is being given to the control of neglected tropical diseases, including the possibility of interrupting the transmission of soil-transmitted helminths (STH). We evaluated the feasibility by country of achieving interruption of the transmission of STH.

METHODS

Based on a conceptual framework for the identification of the characteristics of a successful STH control programme, we assembled spatial data for a range of epidemiological, institutional, economic, and political factors. Using four different statistical methods, we developed a composite score of the feasibility of interrupting STH transmission and undertook a sensitivity analysis of the data and methods.

FINDINGS

The most important determining factors in the analysis were underlying intensity of STH transmission, current implementation of control programmes for neglected tropical diseases, and whether countries receive large-scale external funding and have strong health systems. The composite scores suggested that interrupting STH transmission is most feasible in countries in the Americas and parts of Asia (eg, Argentina [range of composite feasibility scores, depending on scoring method, 9·4-10·0], Brazil [8·7- 9·7], Chile [8·84-10·0], and Thailand [9·1-10·0]; there was perfect agreement between the four methods), and least feasible in countries in sub-Saharan Africa (eg, Congo [0·4-2·7] and Guinea [2·0-5·6]; there was full agreement between methods), but there were important exceptions to these trends (eg, Ghana [7·4-10·0]; there was agreement between three methods). Agreement was highest between the scores derived with the expert opinion and principal component analysis weighting schemes (Pearson correlation coefficient, r=0·98). The largest disagreement was between benefit-of-the-doubt-derived and principal-component-analysis-derived weighting schemes (r=0·74).

INTERPRETATION

The interruption of STH transmission is feasible, especially in countries with low intensity of transmission, supportive household environments, strong health systems, and the availability of suitable delivery platforms and in-country funds, but to achieve local elimination of STH an intersectoral approach to STH control will be needed.

FUNDING

Bill & Melinda Gates Foundation and Wellcome Trust.

Dramatic decrease in prevalence of soil-transmitted helminths and new insights into intestinal protozoa in children living in the Chaco region, Bolivia

We assessed the prevalence of intestinal parasites among 268 2-12-year-old children living in rural areas, small villages, and semi-urban areas of the Chaco region, south-eastern Bolivia. The overall parasitism was 69%. Only protozoa, helminths, or co-infections were observed in 89.2%, 5.9%, or 4.9% of the positive children, respectively. A significant progressive increase in overall parasite prevalence was found when passing from rural areas to small villages and semi-urban areas. The most commonly found species were Entamoeba coli (38.4%), Giardia intestinalis (37.7%), and Blastocystis spp. (16%). Hymenolepis nana was the most prevalent helminth (5.6%), followed by Ascaris lumbricoides and hookworms (1.5% and 0.4%) evidenced only in rural areas and in villages. Molecular diagnostics identified Blastocystis subtypes 9 and 2, and 5 infections by Entamoeba histolytica and 4 by Entamoeba dispar. The dramatic decrease in prevalence of soil-transmitted helminths with respect to that observed about 20 years ago (> 40%) evidences the success of the preventive chemotherapy intervention implemented in 1986. Health education and improved sanitation should be intensified to control protozoan infections.

Macrophage-derived human resistin is induced in multiple helminth infections and promotes inflammatory monocytes and increased parasite burden

Parasitic helminth infections can be associated with lifelong morbidity such as immune-mediated organ failure. A better understanding of the host immune response to helminths could provide new avenues to promote parasite clearance and/or alleviate infection-associated morbidity. Murine resistin-like molecules (RELM) exhibit pleiotropic functions following helminth infection including modulating the host immune response; however, the relevance of human RELM proteins in helminth infection is unknown. To examine the function of human resistin (hResistin), we utilized transgenic mice expressing the human resistin gene (hRetnTg⁺). Following infection with the helminth Nippostrongylus brasiliensis (Nb), hResistin expression was significantly upregulated in infected tissue. Compared to control hRetnTg⁻ mice, hRetnTg⁺ mice suffered from exacerbated Nb-induced inflammation characterized by weight loss and increased infiltration of inflammatory monocytes in the lung, along with elevated Nb egg burdens and delayed parasite expulsion. Genome-wide transcriptional profiling of the infected tissue revealed that hResistin promoted expression of proinflammatory cytokines and genes downstream of toll-like receptor signaling. Moreover, hResistin preferentially bound lung monocytes, and exogenous treatment of mice with recombinant hResistin promoted monocyte recruitment and proinflammatory cytokine expression. In human studies, increased serum resistin was associated with higher parasite load in individuals infected with soil-transmitted helminths or filarial nematode Wuchereria bancrofti, and was positively correlated with proinflammatory cytokines. Together, these studies identify human resistin as a detrimental factor induced by multiple helminth infections, where it promotes proinflammatory cytokines and impedes parasite clearance. Targeting the resistin/proinflammatory cytokine immune axis may provide new diagnostic or treatment strategies for helminth infection and associated immune-mediated pathology.

Parasitic helminths, which infect an estimated two billion people worldwide, represent a significant global public health problem. Infection is associated with life-long morbidity including growth retardation and organ failure. Despite these debilitating conditions, there are currently no successful vaccines against helminths. Further, great variability in the host immune response to helminths exists, with the ability of some individuals to develop immunity, while others are susceptible when re-exposed or maintain life-long chronic infections. Identifying new factors that are differentially expressed in immune versus susceptible individuals could provide new targeting strategies for diagnosis or treatment of helminth infection. Here, we identify an important immunoregulatory function for human resistin in helminth infection. Employing transgenic mice in which the human resistin gene was inserted, we show that human resistin is induced by infection with the helminth Nippostrongylus brasiliensis, where it promotes excessive inflammation and impedes parasite killing. Moreover, analysis of clinical samples from two cohorts of individuals infected with filarial nematodes or soil-transmitted helminths revealed increased resistin and serum proinflammatory cytokines compared to putatively immune individuals. Together, these studies suggest that human resistin is a detrimental cytokine that is expressed in multiple helminth infections, mediates pathogenic inflammation, and delays parasite clearance.

Contamination of public squares and parks with parasites in Erbil city, Iraq

INTRODUCTION AND OBJECTIVE

The soil of public squares and parks may be contaminated with the infective stages of parasites because of the presence of stray animals in these parks. Many people take a rest in these places and they may be at risk of infection with parasites because the infective stages of parasites can survive for months, or even years, in spite of the factors of weather.

OBJECTIVE

To evaluate contamination with the eggs of parasites in the soil of parks in Erbil city, Iraq.

MATERIAL AND METHODS

Forty-eight soil samples were collected from 12 public parks and gardens from 11 different neighbourhoods (8 parks and 3 playgrounds) and one district in Erbil city. The zinc sulfate floatation method was used to recover the eggs of parasites from the samples.

RESULTS

Eggs of parasites were identified in 91.6% of the parks. Eggs of Hymenolepis diminuta were found in 75%, Toxocara spp. in 50%, Ascaris spp. in 33.3%, Taenia spp. in 25%, hookworm in 25%, Trichostrongylus spp. in 16.7% and Trichuris spp. in 16.7% of the parks. Helminth eggs were found in 48% soil samples with a mean number of 1.1 per soil sample. The most contaminated soil sample was found in a park in neighbourhood number 325 with 6 eggs.

CONCLUSIONS

The presence of pathogenic parasites in the soil of parks in Erbil city constitutes a high risk to the people who use these parks for recreation, and requires the appropriate control for these parasites.

Prevalence and associated risk factors of intestinal parasites among children of farm workers in the southeastern Anatolian region of Turkey

OBJECTIVE

To determine the species, prevalence, and associated risk factors of intestinal parasites in farm workers' children in a representative sample in the southeastern Anatolian region of Turkey.

MATERIALS AND METHOD

A total of 333 farm workers' children, under the age of six years, were selected using the probability sampling method. Mean age of the children was 3.63 ± 0.5; 55.5% were female. Data were collected using a structured questionnaire and laboratory analysis of faecal samples.

RESULTS

The overall prevalence was 44.6% and the infected children had single, double, and triple parasitic infections at 72.3%, 23.0%, and 4.7%, respectively. The most common parasite was G. intestinalis (47.97%), followed by E. vermicularis (37.84%), T. saginata (27.03%), H. nana (12.16%), and A. lumbricoides (7.43%), respectively. Age, gender, illiteracy of the households, poverty, absence of toilets, bathrooms, and kitchens at the place of residence, lack of safe potable water, geophagia (soil eating habit), and being a child of a seasonal farmworker were the most significant factors associated with intestinal parasitic infection (P<0.05). G. intestinalis and E. vermicularis were found as the most common parasites that cause salivation, abdominal pain, and tiredness (P<0.05).

CONCLUSION

The study revealed that health education programmes for farm workers and farmers should be improved to increase awareness about living and working conditions, in order to control intestinal parasites. However, early diagnosis and treatment services for intestinal parasites should be provided by primary health care staff in the national child screening programme in agricultural populations.

Modeling the interruption of the transmission of soil-transmitted helminths by repeated mass chemotherapy of school-age children

Background

The control or elimination of neglected tropical diseases has recently become the focus of increased interest and funding from international agencies through the donation of drugs. Resources are becoming available for the treatment of soil-transmitted helminth (STH) infection through school-based deworming strategies. However, little research has been conducted to assess the impact of STH treatment that could be used to guide the design of efficient elimination programs.

Methodology

We construct and analyse an age-structured model of STH population dynamics under regular treatment. We investigate the potential for elimination with finite rounds of treatment, and how this depends on the value of the basic reproductive number R₀ and treatment frequency.

Principal findings

Analysis of the model indicates that its behaviour is determined by key parameter groupings describing the basic reproduction number and the fraction of it attributable to the treated group, the timescale of material in the environment and the frequency and efficacy of treatment. Mechanisms of sexual reproduction and persistence of infectious material in the environment are found to be much more important in the context of elimination than in the undisturbed baseline scenario. For a given rate of drug use, sexual reproduction dictates that less frequent, higher coverage treatment is more effective. For a given treatment coverage level, the lifespan of infectious material in the environment places a limit on the effectiveness of increased treatment frequency.

Conclusions

Our work suggests that for models to capture the dynamics of parasite burdens in populations under regular treatment as elimination is approached, they need to include the effects of sexual reproduction among parasites and the dynamics infectious material in the reservoir. The interaction of these two mechanisms has a strong effect on optimum treatment strategies, both in terms of how frequently to treat and for how long.

The control or elimination of soil-transmitted helminth diseases through chemotherapy has recently become the focus of increased interest and funding from international agencies, charities, and pharmaceutical companies via drug donations for treatment in the poorer regions of the world. The design of treatment regimes and the interpretation of their impact benefit from analysis using robust and reliable mathematical models. By analyzing models of the effect of treatment on host parasite burden, we identify several aspects of parasite natural history and transmission which are often overlooked, but have a marked effect on the impact of treatment strategies. In particular, the inclusion of sexual reproduction and the dynamics of eggs or larval stages in the model changes the response of the parasite population to treatment when parasite burdens are low. This in turn has implications for the design of treatment strategies to eliminate parasites in terms of minimizing total drug use and the length of the program delivering them.

[Intestinal Parasitism in Terena Indigenous People of the Province of Mato Grosso do Sul, Brazil]

OBJECTIVE

Considering that intestinal protozoans and helminths infect more than half of the world population, with high prevalence in the poorest regions, the objective of this study was to conduct parasitological research among indigenous Terena people established in the state of MatoGrosso do Sul. An inquiry was performed to find the incidence of parasitism in these communities.

METHODOLOGY

134 aliquots of feces from individuals of the indigenous community were examined. Samples were conserved in Merthiolate-iodine-formol solution (MIF). The laboratory exams were carried out using the techniques of Hoffman, Pons and Janer; Willis and Kinyoun.

RESULTS

We identified infections of nematode helminths of the species Ascaris lumbricoides, Ancylostomidae, Enterobius vermicularis, Strongyloides stercoralis, and Trichuris trichiura; and cestodes of the species Hymenolepis nana and Taenia spp. Also found were the protozoan species: Cryptosporidium spp., Giardia lamblia, Endolimax nana, Entamoeba coli, and Entamoeba histolytica. 23.1 % of the samples studied were negative. Of the 76.9 % of samples with parasites, there were non-statistically significant differences in parasitism between men and women examined between 1 and 33 years-of-age. There were also no significant differences between monospecific parasitism and with concurrent species. In terms of parasitic diversity, seven species of nematode and cestodes helminths were found along with five species of Archamoebae protozoa: flagellates and enterozoans.

CONCLUSIONS

These results were the basis for orientation and appropriate drug intervention and reveal the need for the implementation governmental, social and educational measures to improve the living conditions of that community.

[Survey of infections of intestinal parasites and related factors in north-west Shandong Province]

OBJECTIVE

To understand the infection status of intestinal parasites and related knowledge and behavior factors of the residents in north-west Shandong Province, so as to provide the evidence for taking targeted preventive measures.

METHODS

Eighteen villages were randomly selected as survey spots by the stratified multi-stage sample method. The Kato-Katz technique was used to detect intestinal parasite eggs among the residents and the cellophane tape anus test was used to detect Enterobius vermicularis eggs among 3-12 years old children. Questionnaires were applied to investigate related knowledge and behavior factors about the intestinal parasite infections in the residents.

RESULTS

Totally 6 366 residents were detected for intestinal parasites and the infection rate was 0.28% (18 cases). Totally 895 children were detected for E. vermicularis and the infection rate was 5.70% (51 cases). Totally 2 915 residents were investigated by questionnaires and the awareness rate of knowledge about preventing parasitic diseases was 26.72%. The formation rates of washing hands before meal and after WC, washing fruit and vegetable before eating, never drinking unboiled water were 55.42%, 42.87%, 43.54% and 83.04% respectively. The awareness rate of knowledge about preventing parasitic diseases of 3-12 years old children was 12.24%; and the formation rates of washing hands before meal and after WC were 47.04% and 30.44% respectively.

CONCLUSIONS

The total infection rate of intestinal parasites is low but the E. vermicularis infection rate is high among children in north-west Shandong Province. The awareness rate of knowledge about preventing parasitic diseases and the formation rates of healthy behaviors are all low. Therefore, the targeted health education should be taken to increase the awareness rate and guide the residents to develop their healthy behaviors.

Neglected tropical diseases among two indigenous subtribes in peninsular Malaysia: highlighting differences and co-infection of helminthiasis and sarcocystosis

Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0-33.0), followed by Giardia spp. (n = 3; 3.1%, -0.3-6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0-13.8), Cryptosporidium spp. (n = 3, 1.8%, -0.2-3.8) and Giardia spp. (n = 2, 1.2%, -0.4-2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.

Molecular paleoparasitological hybridization approach as effective tool for diagnosing human intestinal parasites from scarce archaeological remains

Paleoparasitology is the science that uses parasitological techniques for diagnosing parasitic diseases in the past. Advances in molecular biology brought new insights into this field allowing the study of archaeological material. However, due to technical limitations a proper diagnosis and confirmation of the presence of parasites is not always possible, especially in scarce and degraded archaeological remains. In this study, we developed a Molecular Paleoparasitological Hybridization (MPH) approach using ancient DNA (aDNA) hybridization to confirm and complement paleoparasitological diagnosis. Eight molecular targets from four helminth parasites were included: Ascaris sp., Trichuris trichiura, Enterobius vermicularis, and Strongyloides stercoralis. The MPH analysis using 18th century human remains from Praça XV cemetery (CPXV), Rio de Janeiro, Brazil, revealed for the first time the presence E. vermicularis aDNA (50%) in archaeological sites of Brazil. Besides, the results confirmed T. trichiura and Ascaris sp. infections. The prevalence of infection by Ascaris sp. and E. vermicularis increased considerably when MPH was applied. However, a lower aDNA detection of T. trichiura (40%) was observed when compared to the diagnosis by paleoparasitological analysis (70%). Therefore, based on these data, we suggest a combination of Paleoparasitological and MPH approaches to verify the real panorama of intestinal parasite infection in human archeological samples.

Development of fatal intestinal inflammation in MyD88 deficient mice co-infected with helminth and bacterial enteropathogens

Infections with intestinal helminth and bacterial pathogens, such as enteropathogenic Escherichia coli, continue to be a major global health threat for children. To determine whether and how an intestinal helminth parasite, Heligomosomoides polygyrus, might impact the TLR signaling pathway during the response to a bacterial enteropathogen, MyD88 knockout and wild-type C57BL/6 mice were infected with H. polygyrus, the bacterial enteropathogen Citrobacter rodentium, or both. We found that MyD88 knockout mice co-infected with H. polygyrus and C. rodentium developed more severe intestinal inflammation and elevated mortality compared to the wild-type mice. The enhanced susceptibility to C. rodentium, intestinal injury and mortality of the co-infected MyD88 knockout mice were found to be associated with markedly reduced intestinal phagocyte recruitment, decreased expression of the chemoattractant KC, and a significant increase in bacterial translocation. Moreover, the increase in bacterial infection and disease severity were found to be correlated with a significant downregulation of antimicrobial peptide expression in the intestinal tissue in co-infected MyD88 knockout mice. Our results suggest that the MyD88 signaling pathway plays a critical role for host defense and survival during helminth and enteric bacterial co-infection.

Infections with intestinal helminths and enteric bacterial pathogens such as enteropathogenic Escherichia coli (EPEC) continue to be major global health problems, especially for children. The ability of the host to control bacterial enteropathogens may be influenced by host immune status and by concurrent infections. Helminth parasites are of particular interest in this context because of their ability to modulate host immune responses, and because their geographic distribution coincides with those parts of the world where infections caused by bacterial enteropathogens are most problematic. In this study, we determined how intestinal helminth infection regulates host innate immunity against bacterial enteropathogens by using a murine co-infection model. This model involves co-infection with the intestinal nematode parasite Heligmosomoides polygyrus and the Gram-negative bacterial pathogen Citrobacter rodentium, the murine equivalent of EPEC. The infections were carried out in wild-type mice and in mice lacking MyD88, a protein required for signaling by the Toll-like receptors. We found that co-infection with the helminth parasite significantly worsened Citrobacter-induced colitis in the MyD88-deficient mice, in association with increased mortality and compromised innate immune responses. Our observations demonstrate an important role for MyD88-dependent and -independent signaling in host survival during helminth and enteric bacterial co-infection.

Ruminant self-medication against gastrointestinal nematodes: evidence, mechanism, and origins

Gastrointestinal helminths challenge ruminants in ways that reduce their fitness. In turn, ruminants have evolved physiological and behavioral adaptations that counteract this challenge. Ruminants display anorexia and avoidance behaviors, which tend to reduce the incidence of parasitism. In addition, ruminants appear to learn to self-medicate against gastrointestinal parasites by increasing consumption of plant secondary compounds with antiparasitic actions. This selective feeding improves health and fitness. Here, we review the evidence for self-medication in ruminants, propose a hypothesis to explain self-medicative behaviors (based on post-ingestive consequences), and discuss mechanisms (e.g., enhanced neophilia, social transmission) that may underlie the ontogeny and spread of self-medicative behaviors in social groups. A better understanding of the mechanisms that underlie and trigger self-medication in parasitized animals will help scientists devise innovative and more sustainable management strategies for improving ruminant health and well-being.

Parasitic pneumonia and lung involvement

Parasitic infestations demonstrated a decline in the past decade as a result of better hygiene practices and improved socioeconomic conditions. Nevertheless, global immigration, increased numbers of the immunocompromised people, international traveling, global warming, and rapid urbanization of the cities have increased the susceptibility of the world population to parasitic diseases. A number of new human parasites, such as Plasmodium knowlesi, in addition to many potential parasites, have urged the interest of scientific community. A broad spectrum of protozoal parasites frequently affects the respiratory system, particularly the lungs. The diagnosis of parasitic diseases of airway is challenging due to their wide varieties of clinical and roentgenographic presentations. So detailed interrogations of travel history to endemic areas are critical for clinicians or pulmonologists to manage this entity. The migrating adult worms can cause mechanical airway obstruction, while the larvae can cause airway inflammation. This paper provides a comprehensive review of both protozoal and helminthic infestations that affect the airway system, particularly the lungs, including clinical and roentgenographic presentations, diagnostic tests, and therapeutic approaches.

Different profile of intestinal protozoa and helminthic infections among patients with diarrhoea according to age attending a rural hospital in southern Ethiopia

The aim of this study was to analyze the association of intestinal parasitic diseases with age and gender in patients with diarrhea attending a rural hospital in southern Ethiopia in the period 2007-2012. A total of 32,191 stool examination was performed in patients who presented with diarrhea. The overall prevalence of intestinal parasites in the present study was 26.5%. Predominant parasites detected were Giardia lamblia (15.0%), Entamoeba histolytica/dispar (5.4%), and Ascaris lumbricoides (5.0%). The median of age of diarrheal patients with Hymenolepis species, Schistosoma mansoni and G. lamblia was significantly lower (5 y., 10.5 y., and 18 y., respectively; p<0.001). The median age of diarrheal patients with Taenia species, S. stercoralis, and E. histolytica/dispar was significantly higher (24 y., 24 y., and 20 y., respectively; p<0.01). In conclusion, Giardia lamblia was the most prevalent intestinal parasite and the profile of intestinal parasitic infections is influenced by age.

First survey of helminths in adult goats in Hunan Province, China

The objective of the present survey was to reveal the prevalence of helminths in adult goats in Hunan Province, the People's Republic of China. From July 2010 through February 2013, a total of 479 goats slaughtered in local abattoirs and markets were examined for the presence of helminths using a helminthological approach. Eighty-six percent of the examined goats were infected with at least one species of helminths. In total, 15 genera of helminths were found representing 2 phyla, 3 classes, 5 orders, and 11 families. Oesophago-stomum, Ostertagia and Haemonchus were the most prevailing nematode genera, Eurytrema was the predominant trematode genus detected, whereas the infection of adult goats with cestodes was not common, with Cysticercus tenuicollis being the most common genus. The worm burdens showed obvious seasonal variation in that nematodes and cestodes were abundant in summer and winter, and the trematodes peaked in winter, which was consistent with the seasonal precipitation of Hunan Province. The geographical distribution of helminths in goats ascended with altitude. Goats in the mountainous areas were more severely infected with helminths than goats in the hilly areas, whereas infection of goats with helminths was much less in the lake areas. The present investigation highlights the high prevalence of helminths in adult goats in Hunan Province, China, which provides baseline data for assessing the effectiveness of future prevention and controlling measures against helminth infection in adult goats in this province and elsewhere.

Helminth colonization is associated with increased diversity of the gut microbiota

Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota.

Soil-transmitted helminths are carried by large numbers of people in developing countries. These parasites live in the gut and may interact with bacterial communities in the gut, also called the gut microbiota. To determine whether there are alterations to the gut microbiota that are associated with helminth infections, we examined the types of bacteria present in fecal samples from rural Malaysians, many of whom are helminth-positive and find it likely that helminth colonization alters the gut microbiota for rural Malaysians.

Prevalence of helminthic infections and risk factors in villagers of Nanglae Sub-District, Chiang Rai Province, Thailand

The purposes of the present study were to survey the prevalence of helminthic infections in people living in Nanglae Sub-District of Chiang Rai Province, Thailand from January to March 2013, and to determine factors that correlated with these infections. Two hundred and sixty-three fecal samples were examined for helminth eggs by the use of Kato's thick smear technique. All data were analyzed by descriptive statistics including frequencies, percentages and correlations (Odds ratio [OR] and 95% confidence interval [CI]). The percentage of overall helminthic infections was 11.8%, comprising 6.1% Taenia spp., 4.5%, Ascaris lumbricoides, 0.8%, Strongyloides stercoralis and 0.4% flukes producing opisthorchiid-like eggs. In addition, the prevalence of helminthic infection correlated significantly with the consumption of raw meat (OR = 2.270, 95% CI = 1.047-4.923) and raising dogs in the house (OR = 2.444, 95% CI = 1.080-5.534).

'Seeing is Believing'; the use of novel imaging approaches towards creating a greater understanding of parasite: host interactions

This editorial highlights some of the key points made in the six invited reviews in this special issue of Parasite Immunology on the use of contemporary imaging technologies to investigate the parasite: host interface. Three of the reviews deal with the protozoa Trypanosoma, Leishmania, and Plasmodium, whilst the remainder focus on helminth parasites particularly Schistosoma. The reviews cover aspects related to how the development of transgenic parasites has vastly advanced our understanding of how parasites interact with host cells, particularly as a cause of pathology. Imaging technologies have also been exploited in revealing parasite localisation within host tissues and identifying novel therapeutic targets. Combined the reviews show how 'state of the art' imaging technologies have resulted in a seismic advance in our understanding of parasite biology and how this has the potential to develop new, and improved, strategies to combat disease caused by parasite infections.

Helminth infection increases the probability of indeterminate QuantiFERON gold in tube results in pregnant women

BACKGROUND

Approximately one-third of the world population is infected with M. tuberculosis and helminths (Kariminia et al. (2009), Walson et al. (2010)). Pregnancy and Helminth infection are known to suppress the TH1 response (Kariminia et al. (2009), Elias et al. (2006)) on which the QuantiFERON Gold in Tube (QFT-GIT) assay, that measures the released IFN-γ upon in vitro stimulation with mycobacterial antigens, relies on (Thomas et al. (2010)).

OBJECTIVE

To determine whether QFT-GIT indeterminate result is significantly associated with helminth infection or not.

METHODS

In this cross-sectional study, eighty-five pregnant mothers were screened for parasitic and LTBI using Kato-Katz and QFT-GIT test-respectively,

RESULT

The prevalence of helminth infection in pregnant mothers was 23 (27%) of this 17 (20%) was due to Schistosoma mansoni. Among the total of 85 study participants 26.8% were QFT-GIT positive and 14 (17%) had indeterminate results. Three samples (21.4%) were randomly selected from the indeterminate QFT-GIT results and retested to check the reproducibility of the assay and remained indeterminate. QFT-GIT indeterminate result showed significant association with helminth infection.

CONCLUSION

Helminth infections were significantly associated with indeterminate QFT-GIT results in pregnant mothers. Therefore further study is important to evaluate the possible effect of helminth infection by excluding the effect of pregnancy, as pregnancy also downregulates cellular immunity.

Epizootic and zoonotic helminths of the bobcat (Lynx rufus) in Illinois and a comparison of its helminth component communities across the American Midwest

A total of 6257 helminths of 19 taxa were recovered from the digestive tract and lungs of 67 bobcats in Illinois. Infections caused by Alaria mustelae, Diphyllobothrium latum, and Macracanthorhynchus ingens are reported for the first time in bobcats. From all the taxa recovered, only three species occurred in high prevalence and caused intense infections: Taenia rileyi, Alaria marcianae, and Toxocara cati, with prevalence and mean intensity of 70% and 6; 42% and 193, and 25% and 14 individuals, respectively. Prevalence lower than 15% of 14 helminth species suggests bobcats are not continuously exposed to infective stages of a single parasite, and may be exposed to a large variety of generalists during their lifespan. No significant difference in parasite species according to host sex or age was detected, except for Diphyllobothrium spp., which were found more frequently in females and in trapped bobcats, and the hookworm, Ancylostoma caninum, which infected juveniles more frequently. Average species richness per infracommunity was 2.4 (±1.2), and the parasite component community showed low qualitative similarity with neighbor communities. The taxa A. caninum, Alaria spp., Diphyllobothrium spp., Paragonimus kellicotti, and T. cati are etiological agents of epizootic and zoonotic diseases.

Gastrointestinal parasites of dogs and cats in a refuge in Nakhon Nayok, Thailand

We collected fecal samples from 500 dogs and 300 cats from an animal refuge in Nakhon Nayok Province, Thailand to test for gastrointestinal protozoa and helminths using a formalin-ether concentration technique. The overall prevalence of parasites in stool from dogs was 36.2% (181/500), 35.7% (177/500) had helminths and 2.8% (14/500) had protozoa. The helminths were: hookworm (30.6%), Trichuris vulpis (16.0%), Toxocara canis (6.6%), Hymenolepis diminuta (1.2%), Spirometra mansoni (0.6%), and Dipylidium caninum (0.2%). Giardia duodenalis (2.8%) was found in the stool of dogs. The overall prevalence of parasites in stool from cats was 44.3% (133/300), 43.3% (130/300) were helminths and 6.0% (18/300) were protozoa. The helminths were hookworm (34.7%), T. cati (9.7%), S. mansoni (4.0%), Platynosomum fastosum (2.7%), Strongyloides sp (0.7%), and Echinostoma sp (0.3%). Two species of protozoa, Isospora sp (5.7%) and G. duodenalis (0.3%) were found in the stool of cats. Two percent of dogs and 5.0% of cats had mixed protozoan and helminthic infections. Dogs with double, triple, and quadruple helminthic infections were found at rates of 22.0%, 2.8%, and 0.2%, respectively. Cats with double and triple helminthic infections were found at rates of 9.7% and 1.0%, respectively. Quadruple helminthic infections were not found in cats, and double protozoan infections were not found in either dogs or cats.

Rickettsiae, protozoa, and opisthokonta/metazoa

Rhizobiales (formerly named Rickettsiales) cause in rare instances meningitis and meningovasculitis, respectively. In case of history of exposure, infection by Rhizobiales needs to be considered since both diagnosis and therapy may be extremely difficult and pathogen-specific. The same applies to protozoa; in this chapter, Babesia species, free-living amoebae and Entamoeba histolytica infection, including severe meningitis and brain abscess, infection by Trypanosoma species (South American and African trypanosomiasis) are discussed with respect to history, epidemiology, clinical signs, and symptoms as well as differential diagnosis and therapy. Parasitic flatworms and roundworms, potentially able to invade the central nervous system, trematodes (flukes), cestodes (in particular, Cysticercus cellulosae), but also nematodes (in particular, Strongyloides spp. in the immunocompromised) are of worldwide importance. In contrast, filarial worms, Toxocara spp., Trichinella spp., Gnathostoma and Angiostrongylus spp. are seen only in certain geographically confined areas. Even more regionally confined are infestations of the central nervous system by metazoa, in particular, tongue worms (=arthropods) or larvae of flies (=maggots). The aim of this chapter is (1) to alert the neurologist to these infections, and (2) to enable the attending emergency neurologist to take a knowledgeable history, with an emphasis on epidemiology, clinical signs, and symptoms as well as therapeutic management possibilities.

Spatial analysis and risk mapping of soil-transmitted helminth infections in Brazil, using Bayesian geostatistical models

Soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura and hookworm) negatively impact the health and wellbeing of hundreds of millions of people, particularly in tropical and subtropical countries, including Brazil. Reliable maps of the spatial distribution and estimates of the number of infected people are required for the control and eventual elimination of soil-transmitted helminthiasis. We used advanced Bayesian geostatistical modelling, coupled with geographical information systems and remote sensing to visualize the distribution of the three soil-transmitted helminth species in Brazil. Remotely sensed climatic and environmental data, along with socioeconomic variables from readily available databases were employed as predictors. Our models provided mean prevalence estimates for A. lumbricoides, T. trichiura and hookworm of 15.6%, 10.1% and 2.5%, respectively. By considering infection risk and population numbers at the unit of the municipality, we estimate that 29.7 million Brazilians are infected with A. lumbricoides, 19.2 million with T. trichiura and 4.7 million with hookworm. Our model-based maps identified important risk factors related to the transmission of soiltransmitted helminths and confirm that environmental variables are closely associated with indices of poverty. Our smoothed risk maps, including uncertainty, highlight areas where soil-transmitted helminthiasis control interventions are most urgently required, namely in the North and along most of the coastal areas of Brazil. We believe that our predictive risk maps are useful for disease control managers for prioritising control interventions and for providing a tool for more efficient surveillance-response mechanisms.

Allergic family history as a protective determinant to helminthic infection

OBJECTIVE

Investigate the resistance to helminths in children with an allergic family history.

MATERIAL AND METHOD

The study was undertaken as part of the Prospective Cohort Study of Thai Children (PCTC) that followed all births in the year 2001 from rural districts in Thailand. The family histories of allergic diseases were validated by the physicians'diagnoses and medical record reviews. Fresh stool examinations were carried out at 18 to 36 months of age.

RESULTS

Of 1,076 live births in the cohort, 659 children had complete information. A family history of allergy presented in 5.4% of the children. The prevalence of any helminthic infection, Ascaris lumbricoides, Trichuris trichiura, and hookworm were 25.0%, 18.2%, 9.2%, and 5.3%, respectively. The adjusted odds ratio of a family history of allergy for helminthic infection was 0.28 (95% CI, 0.08-0.95).

CONCLUSION

A family history of allergic diseases independently increases resistance to helminthic infection.

Immunological characteristics of patients infected with common intestinal helminths: results of a study based on reverse-transcriptase PCR

To determine whether common helminth infections could modify the intestinal immunopathological status of the host, the expression in the human duodenal mucosa of cytokines, eosinophil- and mast-cell-specific molecules and monosaccharide transporters of the glucose-transporter (GLUT) family was explored. The 31 subjects were all patients at the gastro-intestinal disease unit of Nongkhai Hospital, Thailand. Four of the 10 patients who presented with eosinophilia (> or = 6.0% of their leucocytes were eosinophils), and five of the other 21 patients, had intestinal infections with helminths when they presented or within the previous 3 months. Studies based on semi-quantitative, reverse-transcriptase PCR revealed that the interleukin-5/interferon-gamma ratio was significantly higher in the noneosinophilic, helminth-infected patients than in the non-eosinophilic, uninfected patients, whereas the IgE receptor type I (Fc epsilon RI)/mast-cell tryptase ratio was significantly higher in the eosinophilic, helminth-infected patients than in the eosinophilic, uninfected patients. Expression of Charcot-Leyden-crystal protein, GLUT-1 and GLUT-5, however, showed no significant inter-group differences. Principal-components analysis of the data on eosinophils, interleukin-5, interferon-gamma, Fc epsilon RI and mast-cell tryptase revealed that one principal component could discriminate the patients who had helminth infection from the non-eosinophilic, uninfected patients, but not from the eosinophilic, uninfected patients. These results indicate that, whatever the intestinal pathology, patients infected with common intestinal helminths tend to develop a mucosal immunological response of the Th2 type.

Effects of hygiene and defecation behavior on helminths and intestinal protozoa infections in Taabo, Côte d'Ivoire

BACKGROUND

More than 1 billion people are currently infected with soil-transmitted helminths and schistosomes. The global strategy to control helminthiases is the regular administration of anthelmintic drugs to at-risk populations. However, rapid re-infection occurs in areas where hygiene, access to clean water, and sanitation are inadequate.

METHODOLOGY

In July 2011, inhabitants from two villages and seven hamlets of the Taabo health demographic surveillance system in south-central Côte d'Ivoire provided stool and urine samples. Kato-Katz and ether-concentration methods were used for the diagnosis of Schistosoma mansoni, soil-transmitted helminths (Ascaris lumbricoides, Trichuris trichiura, and hookworm), and intestinal protozoa. Urine samples were subjected to a filtration method for the diagnosis of Schistosoma haematobium. A questionnaire was administered to households to obtain information on knowledge, attitude, practice, and beliefs in relation to hygiene, sanitation, and defecation behavior. Logistic regression models were employed to assess for associations between questionnaire data and parasitic infections.

PRINCIPAL FINDINGS

A total of 1,894 participants had complete data records. Parasitological examinations revealed prevalences of hookworm, S. haematobium, T. trichiura, S. mansoni, and A. lumbricoides of 33.5%, 7.0%, 1.6%, 1.3% and 0.8%, respectively. Giardia intestinalis and Entamoeba histolytica/E. dispar were detected in 15.0% and 14.4% of the participants, respectively. Only one out of five households reported the presence of a latrine, and hence, open defecation was common. Logistic regression analysis revealed that age, sex, socioeconomic status, hygiene, and defecation behavior are determinants for helminths and intestinal protozoa infections.

CONCLUSIONS/SIGNIFICANCE

We found that inadequate sanitation and hygiene behavior are associated with soil-transmitted helminths and intestinal protozoa infections in the Taabo area of south-central Côte d'Ivoire. Our data will serve as a benchmark to monitor the effect of community-led total sanitation and hygiene education to reduce the transmission of helminthiases and intestinal protozoa infections.

[Detection of four parasitic infections using ELISA]

OBJECTIVE

To study the detection effects of ELISA for the infections of Cysticercus, Echinococcosus, Paragonimus westermani and Sparganum mansoni in order to improve diagnosis.

METHODS

The patients who admitted to Jiangsu Institute of Parasitic Diseases from 2008 to 2001 were selected as the subjects and their sera were detected for IgG against Cysticercus, Echinococcosus, and Paragonimus westermani from January 2008 to March 2011, and IgG against Sparganum mansoni since June, 2011 by ELISA.

RESULTS

A total of 282 cases were detected, and 88 of them were found one or two positive results, and the total positive rate was 31.2%. There were 39, 2, 21, and 3 cases of positive IgG of Cysticercus, Echinococcosus, Paragonimus westermani and Sparganum mansoni, respectively. There were 15 cases of positive IgG to both Cysticercus and Echinococcosus; there were 5 cases of positive IgG to both Cysticercus and Paragonimus westermani; there were 3 cases of positive IgG to both Echinococcosus and Paragonimus westermani. The cross reactions occurred in 23 serum samples among 88 positive samples with a cross reaction rate of 26.1%.

CONCLUSION

There still exist a certain number of patients with parasitic diseases, and the cross reaction may occur in the detection process of IgG to Cysticercus, Echinococcosus, Paragonimus westermani and Sparganum mansoni by ELISA.

Water-related parasitic diseases in China

Water-related parasitic diseases are directly dependent on water bodies for their spread or as a habitat for indispensable intermediate or final hosts. Along with socioeconomic development and improvement of sanitation, overall prevalence is declining in the China. However, the heterogeneity in economic development and the inequity of access to public services result in considerable burden due to parasitic diseases in certain areas and populations across the country. In this review, we demonstrated three aspects of ten major water-related parasitic diseases, i.e., the biology and pathogenicity, epidemiology and recent advances in research in China. General measures for diseases control and special control strategies are summarized.

Influence of physico-chemistry and mineralogy on the occurrence of geohelminths in geophagic soils from selected communities in the Eastern Cape, South Africa, and their possible implication on human health

Geophagic soils from selected communities in Eastern Cape, South Africa were characterised to determine their properties and geohelminth content. The soils were coarse-textured with cation exchange capacity values ranging from 6.35 to 18.94 cmol (+)/kg. Quartz was the dominant mineral in the samples with SiO2, Al2O3, and Fe2O3(t) having the highest concentrations among major element oxides. The soil properties, mineralogical composition, and low amounts of particle binding substances may favour the survival of geohelminth ova in the soils. Seven of the samples contained at least one of the following geohelminths: Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and Strongyloides stercoralis. The presence of these geohelminths in the soils was attributed to agricultural and sanitary practices inherent in the communities and the soil properties. Communities need to be sensitised on the importance of safe sanitary and animal husbandry practices to reduce the prevalence of helminth infection among geophagists.

[Research priorities for the control and elimination of major helminthiases]

In 2009, the Disease Reference Group on Helminth Infections (DRG4) was established by the Special Programme for Research and Training in Tropical Diseases (TDR) to comprehensively review recent advances, identify gaps and rank priorities in helminthiases research towards control and elimination. Six major human helminthiases are targeted, namely onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, food-borne trematodiasis and cysticercosis/taeniasis. Systematic reports made by the DRG4 from such aspects as the impact of helminthiases, control and elimination, interventions, diagnostics, social-ecology and health systems, modeling, basic research and capacity building in research was published in PLoS Neglected Tropical Diseases in 2012. Generalized introduction is presented here and further analysis of its influence on the research of the major helminthiases in China is done.

Gastrointestinal helminths of camels (Camelus dromedarius) in center of Iran

Camels are multipurpose animals in Iran. As parasitic diseases are the major cause of impaired meat and milk production in this animal, the present study aimed at determining gastrointestinal helminthic infections of Iranian camels in the center of the country. Gastrointestinal (GI) tract of 144 carcasses of one-humped camels (Camelus dromedarius) slaughtered in Yazd, Esfahan and Kerman provinces' abattoirs were examined for adult helminths. Camels were from both sexes and different ages. Recovered parasites were identified according to described keys by light microscope. Of 144 tested camels, 117 were infected with at least one helminth species (81.3%). A total of 28 worm species from 14 genera were identified in the digestive tract of infected animals, including 26 species of nematodes and two species of cestodes. The infection rates in stomach, small intestine, and caecum/large intestine were 86.3%, 91.5% and 11.1%, respectively. However, no worm was found in the oesophagus. The recovered worms with infection rates are discussed in this paper. In the present study, Haemonchus tataricus, Trichostrongylus hamatus and Trichuris infundibulus are reported from Iranian dromedaries for the first time. Regarding high prevalence of infection, using anthelminthic drugs seemed necessary to improve the health and productivity of camels. On the other hand, the high rate of zoonotic species indicated that camels have important role in maintaining and transmitting infection to humans.

A comparative study of intestinal helminths in pre-school-age urban and rural children in Morobe Province, Papua New Guinea

Children aged between 1 month and 10 years from one rural coastal locality, two rural upland localities and two urban localities in Morobe Province, Papua New Guinea were examined between September 1980 and September 1982. Hookworm (predominantly Necator americanus), Ascaris lumbricoides and Trichuris trichiura increased in prevalence with age. The prevalence of Strongyloides fuelleborni subspecies kellyi, where present, was either highest in the < 1 year age group or similar in all age groups. N. americanus prevalence was between 59% and 83% in the 3 year age group except at the coastal locality, where it was 15%. A. lumbricoides prevalence in the 3 year age group was very low in one upland locality and between 7% and 41% for the other localities. T. trichiura prevalence in the 3 year age group was between 33% and 55% at the coastal and two urban localities, and very low at the two upland localities. S. f. kellyi prevalence in the < 1 year age group was 48% and 20% respectively at the two upland localities, 2% at one of the urban localities and not detected at the other localities. Strongyloides stercoralis was detected at both urban localities, but not at the coastal locality or at the upland locality where testing was done. Many children had infections of more than one species, and there was a significant association of A. lumbricoides with T. trichiura at the coastal and two urban localities. The presence of S. f. kellyi at one of the urban localities raises the possibility that this once isolated species may now be spreading as infected people visit and settle in the towns. Between 68% and 93% of children in the 3 year age group and between 65% and 100% in the 5 year age group were infected with at least one helminth species.

Relationship between carotid intima media thickness and helminth infections on Flores Island, Indonesia

Objective

To examine the association between helminth infections and atherosclerosis.

Background

Chronic helminth infection, which can lead to poor nutritional status and anti-inflammatory response, might protect against the development of atherosclerosis.

Methods

A cross-sectional study was performed in Flores, Indonesia, an area highly endemic for soil-transmitted helminths (STH). Stool samples from 675 participants aged 18–80 years were collected and screened for Trichuris trichiura by microscopy and for Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, and Strongyloides stercoralis by qPCR. We collected data on body mass index (BMI), waist to hip ratio (WHR), blood pressure, fasting blood glucose (FBG), lipid, high sensitive C-reactive protein (hs-CRP), total immunoglobulin-E (TIgE) and Escherichia coli lipopolysaccharide stimulated cytokines (tumor necrosis factor and interleukin-10). In a subset of 301 elderly adults (≥40 years of age) carotid intima media thickness (cIMT) was measured.

Results

Participants with any STH infection had lower BMI (kg/m2) (mean difference −0.66, 95%CI [−1.26, −0.06]), WHR (−0.01, [−0.02, −0.00]), total cholesterol (mmol/L) (−0.22, [−0.43, −0.01]) and LDL-cholesterol (mmol/L) (−0.20, [−0.39, −0.00]) than uninfected participants. After additional adjustment for BMI the association between helminth infection and total cholesterol (mean difference −0.17, 95%CI [−0.37, 0.03]) as well as LDL-cholesterol (−0.15, [−0.33, 0.04]) was less pronounced. BMI, WHR, and total cholesterol were negatively associated with number species of helminth co-infections. Participants with high TIgE, an indicator of exposure to helminths, had lower FBG, TC, and HDL. The association between TIgE and TC and HDL remained significant after adjustment with BMI. No clear association was found between STH infection or TIgE and mean cIMT.

Conclusions

This cross-sectional study presents evidence that helminth infections were negatively associated with risk factors for cardiovascular disease, an association at least partially mediated by an effect on BMI. The significance of this finding needs to be determined.

Helminth infections and host immune regulation

Helminth parasites infect almost one-third of the world's population, primarily in tropical regions. However, regions where helminth parasites are endemic record much lower prevalences of allergies and autoimmune diseases, suggesting that parasites may protect against immunopathological syndromes. Most helminth diseases are spectral in nature, with a large proportion of relatively asymptomatic cases and a subset of patients who develop severe pathologies. The maintenance of the asymptomatic state is now recognized as reflecting an immunoregulatory environment, which may be promoted by parasites, and involves multiple levels of host regulatory cells and cytokines; a breakdown of this regulation is observed in pathological disease. Currently, there is much interest in whether helminth-associated immune regulation may ameliorate allergy and autoimmunity, with investigations in both laboratory models and human trials. Understanding and exploiting the interactions between these parasites and the host regulatory network are therefore likely to highlight new strategies to control both infectious and immunological diseases.

Empiric deworming to delay HIV disease progression in adults with HIV who are ineligible for initiation of antiretroviral treatment (the HEAT study): a multi-site, randomised trial

BACKGROUND

Co-infection with HIV and helminths is common in sub-Saharan Africa and findings from previous studies have suggested that anthelmintic treatment might delay immunosuppression in people with HIV. We aimed to assess the efficacy of empiric deworming of adults with HIV in delaying HIV disease progression.

METHODS

In this non-blinded randomised trial, we enrolled adults (aged ≥18 years) with HIV who did not meet criteria for the initiation of antiretroviral treatment from three sites in Kenya. Using a computer-generated sequence, we randomly assigned (1:1) eligible participants to either empiric albendazole every 3 months plus praziquantel annually (treatment group) or to standard care (control group). Participants were followed up for 24 months. We measured CD4 cell counts every 6 months and plasma HIV RNA annually. The primary endpoints were a CD4 count of less than 350 cells per μL and a composite endpoint consisting of the first occurrence of a CD4 count of less than 350 cells per μL, first reported use of antiretroviral treatment, and non-traumatic deaths. We compared these measures by use of Cox proportional hazards regression and Kaplan-Meier survival analyses. Primary analysis was done by intention to treat. The trial was registered with ClinicalTrials.gov, number NCT0050722.

FINDINGS

Between Feb 6, 2008, and June 21, 2011, we enrolled and followed-up 948 participants; 469 were allocated to the treatment group and 479 to the control group. All participants were provided with co-trimoxazole prophylaxis. Median baseline CD4 cell counts and HIV RNA concentrations did not differ between groups. We recorded no statistically significant difference between the treatment and control groups in the number of people reaching a CD4 count of fewer than 350 cells per μL (41·6 events per 100 person-years vs 46·2 events per 100 person-years; hazard ratio 0·89, 95% CI 0·75-1·06, p=0·2) or the composite endpoint (44·0 events per 100 person-years vs 49·8 events per 100 person-years; 0·88, 0·74-1·04, p=0·1). Serious adverse events, none of which thought to be treatment-related, occurred at a similar frequency in both groups.

INTERPRETATION

Our findings do not suggest an effect of empiric deworming in the delaying of HIV disease progression in adults with HIV in an area where helminth infection is common. Alternative approaches are needed to delay HIV disease progression in areas where co-infections are common.

Prevalence and intensity of intestinal helminthiasis in children living in orphanages in Benin City, Nigeria

BACKGROUND

Orphans may be envisaged to have sub-optimal care and may be predisposed to high worm burden. This study was undertaken to determine prevalence and intensity of intestinal helminthiasis in children living in orphanages in Benin City, Nigeria.

METHODS

Fresh stool samples from 150 children (0-17 years) living in 10 orphanages in Benin City, were analyzed using the Kato-Katz technique for the detection of ova of helminths between January and April, 2011.

RESULTS

The subjects consisted of 62 (41.3%) males and 88 (58.7%)females; mean age (+/- standard deviation SD) 7.0 +/- 4.6 years, and mean (+/- SD) years lived in the orphanage was 4.0 +/- 3.7 years. Prevalence of intestinal helminthiasis was 20.7% and this prevalence was highest in children ages 12-17years, children who had lived longer years in the orphanages and in orphanages with poor child/care-giver ratio (orphanage F = 12.0: 1 and orphanage H = 7.3: 1). Mean (+/- SD) age (8.7 +/- 4.5 years) of infected subjects was significantly higher than (6.6 +/- 4.5 years) observed in non-infected subjects (p = 0.023). Ascaris lumbricoides and Trichuris trichiura were the intestinal helminths isolated. Intensity of intestinal helminths was light in 24/31 (77.4%) and moderate in 7/31 (22.6%) infected subjects. Median egg per gram was 999 eggs per gram and range was 48-8000.

CONCLUSION

Improved child/care-giver ratio in orphanages will reduce worm burden in orphanages in Benin City.

The incidence of feco-oral parasites in street-food vendors in Buea, south-west region Cameroon

BACKGROUND

The street-food industry lacks legal recognition, it operates in unstable and precarious conditions, involving women and men with minimal or no knowledge of hygienic food handling practices. Infective eggs, bacteria, toxins and cysts of faecal orally transmissible parasites are common agents responsible for food contamination in developing countries.

OBJECTIVE

To determine the incidence of digestive faecal-oral parasites among street-food vendors in Buea, South-west region of Cameroon,

METHODS

From March to May 2009, physical and laboratory analysis of stool samples of 150 randomly selected street-food vendors, residing in four different zones in the municipality were carried out. Information on environmental and personal hygiene was also collected.

RESULTS

Results revealed that 56.7% of the sampled population was infected with faecal-oral parasites. The major faecal-oral parasites detected in stool samples were: Entamoeba coli (14.0%), Entamoeba histolytica (12.67%), Ascaris lumbricoides (11.33%), Ankylostoma duodenalis (10.67%). Childcare activities, lack of deworming, poor personal hygiene, poor sanitary and toilet facilities, were factors promoting the spread of faecal-oral infections.

CONCLUSION

Food vendors should be educated on personal hygiene and safe food handling measures. Regulatory procedures on environmental hygiene and regular medical and paramedical follow up of food vendors should be enforced.

Detection of selected intestinal helminths and protozoa at Hospital Universiti Sains Malaysia using multiplex real-time PCR

Intestinal parasites are the causative agents of a number of important human infections in developing countries. The objective of this study was to determine the prevalence of selected helminths and protozoan infections among patients admitted with gastrointestinal disorders at Hospital Universiti Sains Malaysia, Kelantan, Malaysia using multiplex real-time PCR. In addition microscopic examination was also performed following direct smear, zinc sulphate concentration and Kato-Katz thick smear techniques; and the presence of protozoan parasites was confirmed using trichrome and acid-fast stains. Of the 225 faecal samples analysed, 26.2% were positive for intestinal parasites by the multiplex real-time PCR, while 5.3% were positive by microscopy. As compared to microscopy, the multiplex real-time PCR detected 5.8 and 4.5 times more positives for the selected helminth and protozoan infections respectively. Among the selected helminths detected in this study, hookworm was the most prevalent by real-time PCR, while Ascaris lumbricoides was detected the most by microscopy. Meanwhile, among the selected protozoa detected in this study, Entamoeba histolytica was the most prevalent by real-time PCR, however microscopy detected equal number of cases with E. histolytica and Giardia lamblia. This study showed that real-time PCR can be used to obtain a more accurate prevalence data on intestinal helminths and protozoa.

[Role of infectious agents in the emergence of malignant tumors]

According to the data of the International Agency for Research on Cancer (IARC), at least 6 virus species (HPV, EBV, HHV-8/KSHV, HTLV-1, HBV, HCV), 4 helminthes species (Schistosoma haematobium and japonicum, Opisthorchis viverrini, Clonorchis sinensis) and I bacterium species (Helicobacter pylori) have been proved to be capable of causing the development of cancer. The analysis of the data available shows that Merkel cell polyomavirus (MCV), herpes simplex virus (HSV), John Cunningham polyomavirus (JCV), monkey virus 40 (SV40), cytomegalovirus (CMV), xenotropic murine leukemia virus (XMRV), Helicobacter bilis and hepaticus, Campylobacter jejuni, Fusobacterium varium, enteropathogenic Escherichia coli, enterotoxigenic Bacteroides fragilis, Bacteroides vulgatus, Prevotella spp., Streptococcus bovis and anginosus, Treponema denticola, Salmonella typhi, paratyphi and typhimurium, Borrelia burgdorferi, Bartonella spp., Mycobacterium tuberculosis, Chlamydia pneumoniae, trachomatis and psittaci, Neisseria gonorrhoeae, Propionibacterium acnes, Tropheryma whippelii, Schistosoma mansoni, Opistorchis felineus, Strongyloides stercoralis, Taenia solium, Candida spp., Paracoccidioides brasiliensis, Histoplasma capsulatum and Trichomonas vaginalis can also be potential etiological agents of cancer. Apparently, detection of new associations between infectious agents and risk of the development of cancer will facilitate progress in elaboration of prophylaxis measures, early diagnostic methods and, probably, methods of treatment of malignant tumors.

[The problem of human helminthiasis in the Republic of Bashkortostan]

This investigation was undertaken to study trends in helminthiasis morbidity in the Republic of Bashkortostan in 2009-2011. A total of 1497 subjects who came to the Laboratory of the Department of Microbiology, Virology, and Immunology, Bashkir State Medical University, in 2009-2011, have been randomly selected for this investigation. IgG antibodies were identified in their blood. Enzyme immunoassay has revealed anti-helminth antibodies in 4.7, 4.9, and 4.6% of the examinees in 2009, 2010, and 2011, respectively. Antibodies against Ascaris, Ecchinococcus, Opisthorchis, and Toxocara were most common in the examinees. According to the official statistics, the Republic of Bashkiria showed a 26.4% decrease in helminthiasis morbidity, alterations in the structure of morbidity, and a reduction in the proportion of helminths habiting the intestine, and an increase in the proportion of tissue helminthiases in the period 2006 to 2011.

[Efficiency of standard versus instrumental studies in detecting helminth eggs]

Testing confirmed that the applied brush washing methods developed in the 1970s could provide the adequate representativeness of a sample and full information on the actual presence of helminth eggs in the objects under study. An instrumental study was found to increase the probability of helminth egg detection by up to 3.1 times due to the representativeness of a sample, to reduce the labor- and time-consumption to have analysis results, as well as to unify a procedure for sanitary parasitological studies of washouts, and to enhance the efficiency of the equipment already used in parasitology laboratories.

Evolutionary history of copy-number-variable locus for the low-affinity Fcγ receptor: mutation rate, autoimmune disease, and the legacy of helminth infection

Both sequence variation and copy-number variation (CNV) of the genes encoding receptors for immunoglobulin G (Fcγ receptors) have been genetically and functionally associated with a number of autoimmune diseases. However, the molecular nature and evolutionary context of this variation is unknown. Here, we describe the structure of the CNV, estimate its mutation rate and diversity, and place it in the context of the known functional alloantigen variation of these genes. Deletion of Fcγ receptor IIIB, associated with systemic lupus erythematosus, is a result of independent nonallelic homologous recombination events with a frequency of approximately 0.1%. We also show that pathogen diversity, in particular helminth diversity, has played a critical role in shaping the functional variation at these genes both between mammalian species and between human populations. Positively selected amino acids are involved in the interaction with IgG and include some amino acids that are known polymorphic alloantigens in humans. This supports a genetic contribution to the hygiene hypothesis, which states that past evolution in the context of helminth diversity has left humans with an array of susceptibility alleles for autoimmune disease in the context of a helminth-free environment. This approach shows the link between pathogens and autoimmune disease at the genetic level and provides a strategy for interrogating the genetic variation underlying autoimmune-disease risk and infectious-disease susceptibility.