An Update on the Pathogenesis of Fascioliasis: What Do We Know?

Fasciola hepatica is a trematode parasite distributed worldwide. It is known to cause disease in mammals, producing significant economic loses to livestock industry and burden to human health. After ingestion, the parasites migrate through the liver and mature in the bile ducts. A better understanding of the parasite's immunopathogenesis would help to develop efficacious therapeutics and vaccines. Currently, much of our knowledge comes from in vitro and in vivo studies in animal models. Relatively little is known about the host-parasite interactions in humans. Here, we provide a narrative review of what is currently know about the pathogenesis and host immune responses to F. hepatica summarizing the evidence available from the multiple hosts that this parasite infects.

'Entamoeba histolytica' identified by stool microscopy from children with acute diarrhoea in Peru is not E. histolytica.

Entamoeba histolytica is a rare but feared pathogen owing to its related morbidity and mortality. Physicians in an ambulatory clinic in Cusco noted frequent reports of E. histolytica diagnosed by microscopy. Other non-pathogenic species of Entamoeba have an identical microscopic appearance. To determine whether the organisms were actually E. histolytica, faecal specimens from children aged six months to three years with diarrhoea were tested by a species-specific ELISA for E. histolytica antigen. Although 19/73 patients (26.0%) were presumptively diagnosed with amoebiasis based on microscopy, none were confirmed by ELISA. Most cases diagnosed as E. histolytic by microscopy in Peru are not infected by the pathogenic species and are probably colonised by non-pathogenic amoeba such as Entamoeba dispar.

Infección masiva por Ancylostoma duodenale como causa de hemorragia intestinal y anemia severa / Massive hookworm infection as a cause of intestinal bleeding and severe anemia

El sangrado gastrointestinal masivo causado por uncinarias es raramente reportado. El caso de un paciente varón de 34 años que se presentó con hemorragia digestiva baja con evidencia de infección masiva por uncinarias en la colonoscopia es reportado en este manuscrito. Además, se discute la necesidad de considerar la infección por uncinarias como una posible etiología del sangrado gastrointestinal en áreas endémicas...

Overt gastrointestinal bleeding caused by hookworm infection is rarely reported. We present a 34 year old male with lower gastrointestinal bleeding with evidence of massive hookworm infection on colonoscopy and discuss the need to consider hookworm infection as a possible etiology of gastrointestinal bleed in endemic areas...

Prevalence of intestinal helminths, anemia, and malnutrition in Paucartambo, Peru.

OBJECTIVE: To evaluate the prevalence of soil-transmitted helminth infections, anemia, and malnutrition among children in the Paucartambo province of Cusco region, Peru, in light of demographic, socio-economic, and epidemiologic contextual factors. METHODS: Children from three to twelve years old from six communities in Huancarani district in the highlands of Peru were evaluated for helminth infections, anemia, and nutritional status. Data collected included demographic variables, socioeconomic status, exposures, complete blood counts, and direct and sedimentation stool tests. RESULTS: Of 240 children analyzed, 113 (47%) were infected with one or more parasites. Giardia (27.5%) and Fasciola (9.6%) were the most commonly identified organisms. Eosinophilia was encountered in 21% of the children. Anemia (48.8%) was associated with age (3-4 vs 5-12 years old; odds ratio (OR): 5.86; 95% confidence interval (CI): 2.81-12.21). Underweight (10%) was associated with male sex (OR: 5.97; CI: 1.12-31.72), higher eosinophil count (OR: 4.67; CI: 1.31-16.68) and education of the mother (OR: 0.6; CI: 0.4-0.9). Stunting (31.3%) was associated with education of the mother (OR: 0.83; CI: 0.72-0.95); wasting (2.7%) was associated with higher eosinophil count (OR: 2.75; CI: 1.04-7.25). CONCLUSIONS: Anemia and malnutrition remain significant problems in the Peruvian highlands. These findings suggest that demographic factors, socio-economic status, and possibly parasitic infections intertwine to cause these health problems.

Prevalence of soil-transmitted helminths after mass albendazole administration in an indigenous community of the Manu jungle in Peru.

Few data are available on the epidemiology of soil-transmitted helminths (STHs) in indigenous populations of the Peruvian Amazon. While albendazole is being increasingly used in deworming campaigns, few data exist on the impact of mass drug administration in isolated populations. We studied the prevalence of STHs, anemia, and malnutrition in a Matsigenka ethnic group from the Peruvian Amazon. Participants had received two doses of albendazole on consecutive days, 3 months before and again 2 weeks before data collection. Overall, 290 subjects were included. Most were female (53.7%) and 63.9% were ≤19 years old. Half of the participants had helminth infections. Trichiuris (30.2%), hookworm (19.1%), Ascaris (17.7%), and Strongyloides (5.6%) were the most common helminths. Other helminth ova included Capillaria hepatica and Fasciola-like eggs. Subjects of 5-19 years (51.8 %) and 20-35 years (68.6 %) old had helminths more often than those under 5 years (38%) and older than 35 years (41.5%) (P  =  0.02). Anemia was detected in 41% of children and this was more common in children under 5 years that in those of 5-19 years [odd ratio (OR) = 5.68; 95% CI: 2.71-11.88]. Overall, 72.1% of children were malnourished. Stunting was common in children (70.7%), but wasting was not (2.9%). Despite repeated albendazole administration, this population continued to have a high prevalence of STHs, anemia, and malnutrition. In addition, we detected unusual organisms and organisms that do not respond to albendazole. Further studies are needed to assess the rationale and efficacy of mass chemotherapy for STHs in the Amazon.