Idiopathic CD4+ T lymphocytopenia disclosed after the diagnosis of Visceral leishmaniasis

Diagnosis of Human Trematode Infections

Digenetic trematodes form a major group of human parasites, affecting a large number of humans, especially in endemic foci. Over 100 species have been reported infecting humans, including blood, lung, liver and intestinal parasites. Traditionally, trematode infections have been diagnosed by parasitological methods based on the detection and the identification of eggs in different clinical samples. However, this is complicated due to the morphological similarity between eggs of different trematode species and other factors such as lack of sensitivity or ectopic locations of the parasites. Moreover, the problem is currently aggravated by migratory flows, international travel, international trade of foods and changes in alimentary habits. Although efforts have been made for the development of immunological and molecular techniques, the detection of eggs through parasitological techniques remains as the gold standard for the diagnosis of trematodiases. In the present chapter, we review the current status of knowledge on diagnostic techniques used when examining feces, urine, and sputum and also analyze the most relevant characteristics used to identify eggs with a quick key for the identification of eggs.

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Paleoparasitology and archaeoparasitology in Iran: A retrospective in differential diagnosis

OBJECTIVE

This paper reviews paleo- and archaeoparasitology publications to date, from Iran. The primary focus is the importance of differential diagnosis and the crucial role of interdisciplinary collaborations among parasitologists and other specialists.

METHODS

All relevant articles and theses published in Iran through October 2020 are included and evaluated, with particular emphasis on the diagnostic process.

RESULTS

Archaeoparasitic studies in Iran have identified a number of parasites that provide insight into the past. Misidentification, however, due to incomplete differential diagnosis, remains an issue, as does incomplete description and problematic images.

CONCLUSIONS

Identification of paleoparasites to the species level must be supported with accurate morphology and morphometry. Rigorous differential diagnosis is essential. Caution must be exercised when interpreting observations of ova recovered from coprolites. In these instances, precise identification of host animals and aligning parasite ranges with host specificity is critical. The possibility of incidental parasite presence must be evaluated, including non-specificity of parasite tropisms, transport hosting, or contamination. Lastly, differential diagnosis must include consideration of intentional consumption of parasites. Thus, parasitological findings must be placed in geographical, historical, and cultural contexts.

SIGNIFICANCE

Archaeoparasitological research in Iran has elucidated the presence of faunal and human disease in the past and has, through this reevaluation of the published works, contributed to precise description and diagnosis of ova of roundworms, tapeworms, thorny-headed worms, and recognition of larval stages of tapeworms in recovered remains of mites.

Diagnosis of Human Trematode Infections

Digenetic trematodes form a major group of human parasites, affecting a large number of humans, especially in endemic foci. Over 100 species have been reported infecting humans, including blood, lung, liver, and intestinal parasites. Traditionally, trematode infections have been diagnosed by parasitological methods based on the detection and the identification of eggs in different clinical samples. However, this is complicated due to the morphological similarity between eggs of different trematode species and other factors such as lack of sensitivity or ectopic locations of the parasites. Moreover, the problem is currently aggravated by migratory flows, international travel, international trade of foods, and changes in alimentary habits. Although efforts have been made for the development of immunological and molecular techniques, the detection of eggs through parasitological techniques remains as the gold standard for the diagnosis of trematodiases. In this chapter, we review the current status of knowledge on diagnostic techniques used when examining feces, urine, and sputum and also analyze the most relevant characteristics used to identify eggs with a quick key for the identification of eggs.

Gastrointestinal helminths in farmers and their ruminant livestock from the Coastal Savannah zone of Ghana

To identify the gastrointestinal helminths of veterinary, zoonotic and public health importance in farmers and their ruminant livestock in Ghana, faecal samples were collected from 95 farmers and their livestock (cattle = 328, sheep = 285 and goats = 217) and examined by microscopy and/or molecular techniques. Overall, 21 farmers tested positive for at least one gastrointestinal helminth, 80.9% of which were single infections and 19.0% co-infections. The parasites identified in the farmers consisted of hookworms (n = 13) (9 were Necator americanus and the other 4 could not be amplified by PCR), Trichostrongylus spp. (n = 9), Schistosoma mansoni (n = 1), Schistosoma haematobium (n = 1) and Diphyllobothrium latum (n = 1). In livestock, strongylid nematodes were dominant (56.6%), followed by Paramphistomum spp. (16.9%), Dicrocoelium spp. (7.1%), Thysaniezia spp. (5.8%), Trichuris spp. (3.3%), Moniezia spp. (3.1%), Fasciola spp. (2.8%), Toxocara spp. (1.1%) and Schistosoma spp. (0.2%). Genotyping of Trichostrongylus spp. in the farmer's stools identified six T. colubriformis similar to T. colubriformis detected in cattle, sheep and goats in the study, two Trichostrongylus spp. with 98.3% and 99.2% genetic similarity to T. probolurus respectively and one Trichostrongylus spp. which showed 96.6% similarity to both T. probolurus and T. rugatus. Trichostrongylus axei was also identified in cattle, sheep and goats. This is the first molecular characterisation of Trichostrongylus spp. in Ghana and the species identified in the present study suggests zoonotic transmission from cattle, sheep and goats. Further studies involving larger numbers of farmers and their household members are essential to understand the transmission dynamics and impact of these parasites on farming communities in Ghana.

Administration of interleukin-7 increases CD4 T cells in idiopathic CD4 lymphocytopenia

Idiopathic CD4 lymphopenia (ICL) is a rare syndrome defined by low CD4 T-cell counts (<300/µL) without evidence of HIV infection or other known cause of immunodeficiency. ICL confers an increased risk of opportunistic infections and has no established treatment. Interleukin-7 (IL-7) is fundamental for thymopoiesis, T-cell homeostasis, and survival of mature T cells, which provides a rationale for its potential use as an immunotherapeutic agent for ICL. We performed an open-label phase 1/2A dose-escalation trial of 3 subcutaneous doses of recombinant human IL-7 (rhIL-7) per week in patients with ICL who were at risk of disease progression. The primary objectives of the study were to assess safety and the immunomodulatory effects of rhIL-7 in ICL patients. Injection site reactions were the most frequently reported adverse events. One patient experienced a hypersensitivity reaction and developed non-neutralizing anti-IL-7 antibodies. Patients with autoimmune diseases that required systemic therapy at screening were excluded from the study; however, 1 participant developed systemic lupus erythematosus while on study and was excluded from further rhIL-7 dosing. Quantitatively, rhIL-7 led to an increase in the number of circulating CD4 and CD8 T cells and tissue-resident CD3 T cells in the gut mucosa and bone marrow. Functionally, these T cells were capable of producing cytokines after mitogenic stimulation. rhIL-7 was well tolerated at biologically active doses and may represent a promising therapeutic intervention in ICL. This trial was registered at www.clinicaltrials.gov as #NCT00839436.

Human infections with Dicrocoelium dendriticum in Kyrgyzstan: the tip of the iceberg?

Dicrocoelium dendriticum is the causative agent of a rare food-borne zoonosis of the human biliary tract, dicrocoeliasis, for which few human prevalence data are available. Infection occurs through the ingestion of ants containing metacercariae, whereas pseudo-infections (presence of D. dendriticum eggs in stool in the absence of adult worms) are due to the consumption of infected animal liver. Here, results from a cross-sectional survey carried out among 138 children aged 2-15 yr in a peri-urban area of Kyrgyzstan are reported. Each child provided 1 stool sample that was subjected to the FLOTAC technique. Eggs of D. dendriticum were diagnosed in 11 children (prevalence 8.0%; 95% confidence interval 4.5-13.7%). Although no distinction could be made between true and pseudo-infections, the prevailing animal husbandry system and the diet and hygienic conditions of the study area suggest that the social-ecological system in Kyrgyzstan is conducive for human transmission of D. dendriticum. There is a need to investigate the epidemiology of dicrocoeliasis in Kyrgyzstan, placing emphasis on the distinction between true and pseudo-infections.