Impact of parasitic infection on mental health and illness in humans in Africa: a systematic review.

A growing body of research implicates inflammation as a potential pathway in the aetiology and pathophysiology of some mental illnesses. A systematic review was conducted to determine the association between parasitic infection and mental illnesses in humans in Africa and reviewed the state of the evidence available. The search focused on publications from Africa documenting the relationship between parasites from two parasite groups, helminths and protozoans, and four classifications of mental illness: mood affective disorders, neurotic and stress-related disorders, schizotypal disorders and unspecified mental illnesses. In the 26 reviewed papers, the prevalence of mental illness was significantly higher in people with parasitic infection compared to those without infection, i.e., 58.2% vs 41.8% (P < 0.001). An overall odds ratio found that the association of having a mental illness when testing positive for a parasitic infection was four times that of people without infection. Whilst the study showed significant associations between parasite infection and mental illness, it also highlights gaps in the present literature on the pathophysiology of mental illness in people exposed to parasite infection. This study highlighted the importance of an integrated intervention for parasitic infection and mental illness.

Community perceptions of mass drug administration for soil-transmitted helminthiasis and schistosomiasis in selected schools in the Philippines.

BACKGROUND: Soil-transmitted helminthiasis (STH) and schistosomiasis are parasitic infections prevalent in tropical and subtropical countries, such as the Philippines. The prevalence of these infections remain high in certain Philippine provinces, despite established mass drug administration (MDA) programs in endemic communities. This study aimed to understand community knowledge and perceptions of these infections to determine their implications on the current control and elimination strategies, including possible barriers to MDA compliance. METHODS: The study was conducted in Northern Samar and Sorsogon, two provinces with the highest STH and schistosomiasis prevalence in the country. Focus group discussions with separate parent and children groups were utilized to gather knowledge and perceptions on STH and schistosomiasis causes, symptoms, treatment, and prevention; and on the deworming drugs and overall program implementation. Data collection in Northern Samar were done in August 2017, while the sessions in Sorsogon took place in May 2018. A cultural construction of disease framework will show how several factors affect MDA participation. RESULTS: Results showed that participants held mostly correct biomedical notions of the infections and expressed willingness to participate in MDA program. However, reservations remained due to a reported lack of information dissemination, lack of confidence in the drugs used, and widespread fear of adverse side effects. CONCLUSION: Addressing these concerns - improving the conduct of the deworming program, incorporating suggestions from the community, and managing potential adverse events - may help raise MDA participation and encourage better personal preventive practices, reducing STH and schistosomiasis prevalence. TRIAL REGISTRATION: N/A.

A longitudinal cohort study of soil-transmitted helminth infections during the second year of life and associations with reduced long-term cognitive and verbal abilities.

BACKGROUND: Soil-transmitted helminth (STH) infection leads to malnutrition and anemia, and has been linked to impaired child development. Previous research on this topic is limited and mostly conducted in school-age children. The goal of this study was to determine the effect of the number of detected STH infections between one and two years of age on subsequent cognitive and verbal abilities, in a cohort of preschool children. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal cohort study was conducted in 880 children in Iquitos, Peru between September 2011 and July 2016. Children were recruited at one year of age and followed up at 18 months and then annually between two and five years of age. STH infection was measured with the Kato-Katz technique or the direct smear technique. Child development was measured with the Bayley Scales of Infant and Toddler Development-III at the one to three-year visits and with the Wechsler Preschool and Primary Scale of Intelligence-III at the four and five-year visits. Hierarchical multivariable linear regression models were used to account for the repeated outcome measures for each child and Bayesian latent class analysis was used to adjust for STH misclassification. Children found infected with any STH infection between one and two years of age had lower cognitive scores between two and five years of age (between group score differences (95% credible intervals) for infected once, and infected two or three times, compared to never infected: -4.31 (-10.64, -0.14) and -3.70 (-10.11, -0.11), respectively). Similar results were found for Ascaris infection and for verbal scores. CONCLUSIONS/SIGNIFICANCE: An association was found between having been infected with Ascaris or any STH between one and two years of age and lower cognitive and verbal abilities later in childhood. These results suggest that targeting children for STH control as of one year of age is particularly important.

Knowledge, practices and perceptions of geo-helminthes infection among parents of pre-school age children of coastal region, Kenya.

BACKGROUND: Soil-transmitted helminthes (STHs) are common human parasitic diseases in most of the developing world particularly in Kenya. The ongoing National School-Based Deworming Programme (NSBDP) was launched in 2012 and is currently targeting 28 of the 47 endemic Counties. In an effort to improve treatment intervention strategies among Pre-School Age Children (PSAC) attending Early Childhood Development Centres (ECDC), we sought to assess parents' knowledge, perceptions and practices on worm infection. METHODOLOGY: We conducted a qualitative cross-sectional study in four endemic sub-counties of two counties of coastal region of Kenya. A total of 20 focus group discussions (FGDs) categorized by gender were conducted among parents of pre-school age children. Participants were purposively selected based on homogenous characteristics with the saturation model determining the number of focus group discussions conducted. The data collected was analyzed manually by study themes. FINDINGS: The majority of the parents had knowledge on worms and modes of transmission of the parasitic infections among the pre-school children. Also, most of the participants knew the causes of worm infection and the pre- disposing factors mentioned included poor hygiene and sanitation practices. Due to poor knowledge of signs and symptoms, misconceptions about the drugs administered during the NSBDP were common with a large majority of the parents indicating that the drugs were ineffective in worm control. The findings also indicated that most of the participants sought medical care on the onset of the signs and symptoms of worm infestation and preferred services provided at public health facilities as opposed to private health facilities or buying drugs from the local market citing mistrust of such services. Cultural beliefs, high cost of building and availability of vast pieces of land for human waste disposal were factors that contributed to low or lack of latrine ownership and usage by a large majority of the respondents. CONCLUSIONS: Our results show that to a large extent the parents of the pre-school age children have information on worm infections. However, some cultural beliefs and practices on the pathology and mode of transmission mentioned could be a hindrance to prevention and control efforts. There is need to implement health promotion campaigns to strengthen the impact of control strategies and reduce infection.

Gut microbiota disturbance during helminth infection: can it affect cognition and behaviour of children?

BACKGROUND: Bidirectional signalling between the brain and the gastrointestinal tract is regulated at neural, hormonal, and immunological levels. Recent studies have shown that helminth infections can alter the normal gut microbiota. Studies have also shown that the gut microbiota is instrumental in the normal development, maturation and function of the brain. The pathophysiological pathways by which helminth infections contribute to altered cognitive function remain poorly understood. DISCUSSION: We put forward the hypothesis that gastrointestinal infections with parasitic worms, such as helminths, induce an imbalance of the gut-brain axis, which, in turn, can detrimentally manifest in brain development. Factors supporting this hypothesis are: 1) research focusing on intelligence and school performance in school-aged children has shown helminth infections to be associated with cognitive impairment, 2) disturbances in gut microbiota have been shown to be associated with important cognitive developmental effects, and 3) helminth infections have been shown to alter the gut microbiota structure. Evidence on the complex interactions between extrinsic (parasite) and intrinsic (host-derived) factors has been synthesised and discussed. While evidence in favour of the helminth-gut microbiota-central nervous system hypothesis is circumstantial, it would be unwise to rule it out as a possible mechanism by which gastrointestinal helminth infections induce childhood cognitive morbidity. Further empirical studies are necessary to test an indirect effect of helminth infections on the modulation of mood and behaviour through its effects on the gut microbiota.

Improved Perceptions and Practices Related to Schistosomiasis and Intestinal Worm Infections Following PHAST Intervention on Kome Island, North-Western Tanzania.

Schistosomiasis and intestinal worm infections are widespread diseases of public health importance in Tanzania. A study on perceptions and practices related to schistosomiasis and intestinal worm infections was undertaken among a community population of Kome Island in Sengerema District, north-western Tanzania, where intestinal schistosomiasis and intestinal worm infections are endemic. Schistosomiasis and intestinal worm-related perceptions and practices were assessed before and 3 years after implementation of a participatory hygiene and sanitation transformation (PHAST) intervention as a control measure. Data were obtained from baseline and post-intervention knowledge, attitudes, and practices (KAP) questionnaire surveys conducted twice in 2009 and 2012 among 82 individuals aged ≥15 years. We found significant increases in respondents' knowledge of the cause, transmission, symptoms, health consequences, and prevention of schistosomiasis and intestinal worm infections after PHAST intervention. The increase in respondents' knowledge on almost all aspects of the said infections was translated into actions to control schistosomiasis and intestinal worm infections. This has not been achieved by chance, but due to well-designed and locally-adapted PHAST intervention. We conclude that despite criticisms, PHAST approach is still useful in empowering communities to control water, sanitation, and hygiene related infectious diseases such as schistosomiasis and intestinal worm infections.

Gut instincts: knowledge, attitudes, and practices regarding soil-transmitted helminths in rural China.

BACKGROUND: Soil-transmitted helminth (STH) infections affect more than two out of every five schoolchildren in the poorest regions of rural China, an alarmingly high prevalence rate given the low cost and wide availability of safe and effective deworming treatment. Understanding of local knowledge, attitudes, and practices regarding STH infection in rural China has until now, been sparse, although such information is critical for prevention and control initiatives. METHODOLOGY/PRINCIPAL FINDINGS: This study aims to elucidate the structural and sociocultural factors that underlie high STH infection rates as well as explain why deworming treatment is rarely sought for children. In-depth, qualitative interviews were conducted in six rural villages in Guizhou Province; participants included schoolchildren, children's parents and grandparents, and village doctors. Data analysis exposed three predominant reasons for high STH prevalence: (1) lack of awareness and skepticism about the high prevalence of STH infection, (2) local myths about STH infection and deworming treatment, and (3) poor quality of village health care. CONCLUSIONS/SIGNIFICANCE: The findings from this study reveal reasons for why deworming treatment is not sought, and inform specific recommendations for a deworming intervention that can more effectively address underlying barriers to deworming in areas of persistently high STH infection rates. The main barrier to seeking STH treatment is not availability or cost of the drugs, but rather the lack of impetus to seek the drugs. A comprehensive nationwide deworming program in China should involve annual provision of free deworming treatment in village clinics or schools, distribution of culturally appropriate educational materials to inform children and families about STH infection, and improvement of the quality of health care delivered by village clinicians.

Impact of helminth infection during pregnancy on cognitive and motor functions of one-year-old children.

OBJECTIVE: To determine the effect of helminth infection during pregnancy on the cognitive and motor functions of one-year-old children. METHODS: Six hundred and thirty five singletons born to pregnant women enrolled before 29 weeks of gestation in a trial comparing two intermittent preventive treatments for malaria were assessed for cognitive and motor functions using the Mullen Scales of Early Learning, in the TOVI study, at twelve months of age in the district of Allada in Benin. Stool samples of pregnant women were collected at recruitment, second antenatal care (ANC) visit (at least one month after recruitment) and just before delivery, and were tested for helminths using the Kato-Katz technique. All pregnant women were administered a total of 600 mg of mebendazole (100 mg two times daily for 3 days) to be taken after the first ANC visit. The intake was not directly observed. RESULTS: Prevalence of helminth infection was 11.5%, 7.5% and 3.0% at first ANC visit, second ANC visit and at delivery, respectively. Children of mothers who were infected with hookworms at the first ANC visit had 4.9 (95% CI: 1.3-8.6) lower mean gross motor scores compared to those whose mothers were not infected with hookworms at the first ANC visit, in the adjusted model. Helminth infection at least once during pregnancy was associated with infant cognitive and gross motor functions after adjusting for maternal education, gravidity, child sex, family possessions, and quality of the home stimulation. CONCLUSION: Helminth infection during pregnancy is associated with poor cognitive and gross motor outcomes in infants. Measures to prevent helminth infection during pregnancy should be reinforced.

Helminth Therapy for MS.

In the last 50 years, environmental factors such as helminth infections have been proposed to explain why autoimmunity is less prevalent in the developing world; this proposal has been termed the hygiene or old friends hypothesis. The epidemiology of MS shows an inverse correlation with helminth infections. Positive effects of helminths in animal models of MS and observational studies in people with MS naturally infected with helminths suggest that those organisms can act as immune regulators and led to clinical trials of helminth therapy. The goal of helminth therapy is to introduce parasitic organisms into people with MS in a controlled and predictable fashion, and to prevent immune-mediated disease without increasing the risk of pathology with high parasite load. This chapter focuses on intestinal worms as they are the current choice as a therapeutic strategy in a number of autoimmune diseases, including MS. Here we review current data regarding the rationale and the current state of research in the field of helminth therapies in MS.

Effect of deworming on school-aged children's physical fitness, cognition and clinical parameters in a malaria-helminth co-endemic area of Côte d'Ivoire.

BACKGROUND: Malaria and helminth infections are thought to negatively affect children's nutritional status and to impair their physical and cognitive development. Yet, the current evidence-base is weak. The purpose of this study was to determine the effect of deworming against soil-transmitted helminthiasis and schistosomiasis on children's physical fitness, cognition and clinical parameters in a malaria-helminth co-endemic setting of Côte d'Ivoire. METHODS: We designed an intervention study with a 5-month follow-up among schoolchildren aged 5-14 years from Niablé, eastern Côte d'Ivoire. In late 2012, a baseline cross-sectional survey was conducted. Finger-prick blood, stool and urine samples were subjected to standardised, quality-controlled techniques for the diagnosis of Plasmodium spp., Schistosoma spp., soil-transmitted helminths and intestinal protozoa infections. Haemoglobin level was determined and anthropometric measurements were taken for appraisal of anaemia and nutritional status. Children underwent memory (digit span) and attention (code transmission) cognitive testing, and their physical fitness and strength were determined (20 m shuttle run, standing broad jump and grip strength test). All children were treated with albendazole (against soil-transmitted helminthiasis) and praziquantel (against schistosomiasis) after the baseline cross-sectional survey and again 2 months later. Five months after the initial deworming, the same battery of clinical, cognitive and physical fitness tests was performed on the same children. RESULTS: Lower scores in strength tests were significantly associated with children with harbouring nutritional deficiencies. Surprisingly, boys infected with Schistosoma mansoni achieved longer jumping distances than their non-infected counterparts. Light-intensity infection with S. mansoni was associated with slightly better aerobic capacity. Deworming showed no effect on haemoglobin levels and anaemia, but children with moderate- to heavy-intensity Schistosoma infection at baseline gained weight more pronouncedly than non-infected children. Interestingly, children with soil-transmitted helminth or Schistosoma infection at baseline performed significantly better in the sustained attention test than their non-infected counterparts at the 5-month follow-up. CONCLUSIONS: This study revealed conflicting results regarding clinical parameters and cognitive behaviour of children after two rounds of deworming. We speculate that potential beneficial effects of deworming are likely to be undermined in areas where malaria is co-endemic and nutritional deficiencies are widespread.

Low levels of awareness despite high prevalence of schistosomiasis among communities in Nyalenda informal settlement, Kisumu city, western Kenya.

INTRODUCTION: Intestinal schistosomiasis is widely distributed around Lake Victoria in Kenya where about 16 million people in 56 districts are at risk of the infection with over 9.1 million infected. Its existence in rural settings has been extensively studied compared to urban settings where there is limited information about the disease coupled with low level of awareness. This study therefore assessed community awareness on existence, signs and symptoms, causes, transmission, control and risk factors for contracting schistosomiasis as well as attitudes, health seeking behaviour and environmental antecedents that affect its control so as to identify knowledge gaps that need to be addressed in order to strengthen schistosomiasis control interventions in informal urban settings. METHODS: The study was carried out in an informal urban settlement where the prevalence of intestinal schistosomiasis was previously reported to be the highest (36%) among the eight informal settlements of Kisumu city. The study adopted cross-sectional design and purposive sampling technique. Eight focus group discussions were conducted with adult community members and eight key informant interviews with opinion leaders. Data was audio recorded transcribed, coded and thematically analyzed using ATLAS.ti version 6 software. RESULTS: Most respondents stated having heard about schistosomiasis but very few had the correct knowledge of signs and symptoms, causes, transmission and control of schistosomiasis. However, there was moderate knowledge of risk factors and at high risk groups. Their attitudes towards schistosomiasis and its control were generally indifferent with a general belief that they had no control over their environmental circumstances to reduce transmission. DISCUSSION/CONCLUSION: Although schistosomiasis was prevalent in the study area, majority of the people in the community had low awareness. This study, therefore, stresses the need for health education to raise community's awareness on schistosomiasis in such settings in order to augment prevention, control and elimination efforts.

Towards an effective control programme of soil-transmitted helminth infections among Orang Asli in rural Malaysia. Part 2: Knowledge, attitude, and practices.

BACKGROUND: In the first part of this study, we investigated the prevalence and associated key factors of soil-transmitted helminth (STH) infections among Orang Asli children in rural Malaysia; an alarming high prevalence and five key factors significantly associated with infections were reported. Part 2 of this study aims to evaluate the knowledge, attitude and practices (KAP) on STH infections among Orang Asli in Peninsular Malaysia. METHODS: A cross-sectional study was carried out among 215 households from 13 villages in Lipis district, Pahang, Malaysia. Demographic and socioeconomic information of the participants and their KAP on STH were collected by using a pre-tested questionnaire. RESULTS: Overall, 61.4% of the participants had prior knowledge about intestinal helminths with a lack of knowledge on the transmission (28.8%), signs and symptoms (29.3%) as well as the prevention (16.3%). Half of the respondents considered STH as harmful, while their practices to prevent infections were still inadequate. Significant associations between the KAP and age, gender, educational and employment status, family size, and household monthly income were reported. Moreover, significantly lower prevalence of STH infections was reported among children of respondents who wear shoes/slippers when outside the house (72.8%; 95% CI= 62.6, 80.5 vs 87.0%; 95% CI= 81.4, 91.1), wash their hands before eating (32.4%; 95% CI= 24.3, 42.2 vs 51.4%; 95% CI= 44.7, 60.1), and wash their hands after defecation (47.8%; 95% CI= 35.7, 57.1 vs 69.2%; 95% CI= 63.7, 78.7) as compared to their counterparts. Multiple logistic regression analysis indicated that the educational level of the respondents was the most important factor significantly associated with the KAP on STH among this population. CONCLUSION: This study reveals inadequate knowledge, attitude and practices on STH infections among Orang Asli in rural Malaysia. Hence, there is a great need for a proper health education programme and community mobilisation to enhance prevention and instil better knowledge on STH transmission and prevention. This is crucial for an effective and sustainable STH control programme to save the lives and future of the most vulnerable children in rural Malaysia.

Nitazoxanide: a new broad spectrum antiparasitic agent.

Nitazoxanide (Alinia, Romark Laboratories) was synthesized based on the structure of niclosamide. In vitro studies have demonstrated activity against a broad range of parasites as well as some bacteria. Three controlled trials demonstrated efficacy in cryptosporidiosis, however, the efficacy in advanced AIDS patients (CD4 cell counts = 50) at approved doses was limited. Trials have also demonstrated efficacy comparable to metronidazole (Flagyl, GD Searle and Co.) in giardiasis with fewer side effects. Nitazoxanide is also effective versus intestinal helminths and tapeworms as well as in chronic fascioliasis. Side effects in clinical trials have been similar to placebo. Nitazoxanide is the first agent proven to be effective in cryptosporidiosis. It has also proven efficacy in giardiasis. Nitazoxanide is efficacious again intestinal helminths. Additional indications may be developed in the future.

Atypical antipsychotics in the treatment of delusional parasitosis.

Delusional parasitosis is the false belief that one's body is infested with one or many different living organisms. Historically, it has been treated with conventional antipsychotics with only moderate success. The conventional antipsychotic most commonly used has been pimozide. We report a series of five cases of patients with delusional parasitosis. Our patients' demographic characteristics were similar to those in previously published case reports, but instead of being treated with older antipsychotics, they were all treated with atypical antipsychotic agents with favorable results. We will discuss the rationale for this treatment choice, and will review the role of serotonin/dopamine antagonists in the treatment of delusional parasitosis. We will also comment on the possible role of serotonergic antidepressants in the treatment of these patients.

Effects of two acanthocephalan parasites on the fecundity and pairing status of female Gammarus pulex (Crustacea: Amphipoda).

Acanthocephalan parasites are known to alter the reproductive biology and physiology of their hosts in various ways. In this study we investigated the influence of two acanthocephalan parasites, Pomphorhynchus laevis and Polymorphus minutus, on the fecundity and pairing success of female Gammarus pulex. The results show that P. laevis and P. minutus affect female intermediate host reproduction in different ways. Females infected with P. minutus were totally castrated, whereas those infected with P. laevis only showed reduced fecundity. The oocytes of P. laevis-infected females showed a similar structure to those of uninfected females, although infected females had a higher proportion of oocytes that had failed to reach complete maturity. In comparison, the oocytes of P. minutus-infected females demonstrate a clearly altered structure that suggests a major disruption to the process of vitellogenesis. In the field, males paired more frequently with uninfected females than with infected ones, and is a stronger effect for P. minutus-infected females than P. laevis-infected females. We suggest that the difference in pairing success of P. minutus-infected and P. laevis-infected females is a direct result of the different effects that the two parasites have on female fecundity.

Effects of iron supplementation and anthelmintic treatment on motor and language development of preschool children in Zanzibar: double blind, placebo controlled study.

OBJECTIVE: To measure the effects of iron supplementation and anthelmintic treatment on iron status, anaemia, growth, morbidity, and development of children aged 6-59 months. DESIGN: Double blind, placebo controlled randomised factorial trial of iron supplementation and anthelmintic treatment. SETTING: Community in Pemba Island, Zanzibar. PARTICIPANTS: 614 preschool children aged 6-59 months. MAIN OUTCOME MEASURES: Development of language and motor skills assessed by parental interview before and after treatment in age appropriate subgroups. RESULTS: Before intervention, anaemia was prevalent and severe, and geohelminth infections were prevalent and light-Plasmodium falciparum infection was nearly universal. Iron supplementation significantly improved iron status, but not haemoglobin status. Iron supplementation improved language development by 0.8 (95% confidence interval 0.2 to 1.4) points on the 20 point scale. Iron supplementation also improved motor development, but this effect was modified by baseline haemoglobin concentrations (P=0.015 for interaction term) and was apparent only in children with baseline haemoglobin concentrations <90 g/l. In children with a baseline haemoglobin concentration of 68 g/l (one standard deviation below the mean value), iron treatment increased scores by 1.1 (0.1 to 2.1) points on the 18 point motor scale. Mebendazole significantly reduced the number and severity of infections caused by Ascaris lumbricoides and Trichuris trichiura, but not by hookworms. Mebendazole increased development scores by 0.4 (-0.3 to 1.1) points on the motor scale and 0.3 (-0.3 to 0.9) points on the language scale. CONCLUSIONS: Iron supplementation improved motor and language development of preschool children in rural Africa. The effects of iron on motor development were limited to children with more severe anaemia (baseline haemoglobin concentration <90 g/l). Mebendazole had a positive effect on motor and language development, but this was not statistically significant.

Delusion of infestation with post-partum onset: case report.

Compared with men, women have a greater lifetime risk of delusions of infestation, with the risk appearing to increase around the menopause, when the blood levels of reproductive hormones are decreasing. Women also have a greater lifetime risk of depression and an increased incidence of depressive symptoms post partum, when the blood levels of these hormones are decreasing as well. The first case of a delusion of infestation with post-partum onset is described, and possible associations with reproductive function in women are discussed.

Attitudes towards helminthic infection in the Jirel population of eastern Nepal.

Intestinal worm infections, including roundworm, hookworm, and whipworm, are major international health concerns, affecting approximately one fourth of the world's population. Many intervention schemes have been attempted to control these infections in heavily exposed populations, but success has been limited because individuals are readily reinfected upon renewed exposure. Few data are available concerning people's health beliefs about soil-transmitted helminthic infections in such populations. The purpose of this study was to assess health beliefs about common helminthiasis in a population experiencing moderate to high rates of infection. The focal population for the study was the Jirel population, a tribal group distributed across nine villages in the Jiri Region of Dolakha District, eastern Nepal. The results indicate that beliefs about the types, causes, and treatments of helminthic infections have been developed and reinforced by experience and empirical evidence. People's frequent inability to confirm the efficacy of drug therapy by observing worms in stools has led to dissatisfaction with biomedical approaches. Carefully planned education programs are required to alter prevailing attitudes and improve control of soil-transmitted helminthiasis in the region.