The opportunistic protist, Giardia intestinalis, occurs in gut-healthy humans in a high-income country

Giardia intestinalis, a cosmopolitan gastrointestinal protist, is detected mainly in patients with clinical giardiasis in high-income countries. In contrast, there is very little information on the presence of Giardia in asymptomatic individuals. Therefore, the aim of this study was to determine the presence and prevalence of Giardia in gut-healthy volunteers in the Czech Republic and to perform a comparative evaluation of different diagnostic methods, since Giardia diagnostics is complicated. Our results confirmed that the qPCR method is the most sensitive method for detecting Giardia and revealed a prevalence of 7% (22/296) in asymptomatic individuals. In most cases, the colonization intensity ranged from 10-1-101. A conventional PCR protocol targeting the TPI gene was used to identify the assemblages. However, this protocol had limited sensitivity for Giardia amplification, effectively detecting colonization above an intensity of 104. In addition, Giardia was detected in 19% of the animals, which were closely associated with the study participants. However, due to methodological limitations, zoonotic transmission could not be clearly confirmed. Notably, contact with animals proved to be the only factor that had a significant impact on the incidence of Giardia in gut-healthy humans.

A Cross-Sectional Study on the Occurrence of the Intestinal Protist, Dientamoeba fragilis, in the Gut-Healthy Volunteers and Their Animals

Dientamoeba fragilis is a cosmopolitan intestinal protist colonizing the human gut with varying prevalence depending on the cohort studied and the diagnostic methods used. Its role in human health remains unclear mainly due to the very sporadic number of cross-sectional studies in gut-healthy populations. The main objective of this study was to expand knowledge of the epidemiology of D. fragilis in gut-healthy humans and their animals. A total of 296 stool samples from humans and 135 samples from 18 animal species were analyzed. Using qPCR, a prevalence of 24% was found in humans in contrast to conventional PCR (7%). In humans, several factors were found to influence the prevalence of D. fragilis. A more frequent occurrence of D. fragilis was associated with living in a village, traveling outside Europe and contact with farm animals. In addition, co-infection with Blastocystis spp. was observed in nearly half of the colonized humans. In animals, D. fragilis was detected in 13% of samples from eight species using qPCR. Our molecular phylogenies demonstrate a more frequent occurrence of Genotype 1 in gut-healthy humans and also revealed a likely a new protist species/lineage in rabbits related to D. fragilis and other related organisms.

A Study on the Prevalence and Subtype Diversity of the Intestinal Protist Blastocystis sp. in a Gut-Healthy Human Population in the Czech Republic

Blastocystis sp. is a common intestinal protist colonizing the human intestine the prevalence of which varies across non-industrialized and industrialized countries. Its role in the human gut ecosystem remains unclear due to persisting gaps in knowledge of epidemiology and factors affecting gut colonization. Here, we aimed to expand the knowledge of the epidemiology of Blastocystis sp. in the gut-healthy humans in one of the industrialized European countries, including the distribution of its subtypes, the correlation between its occurrence and several factors such as lifestyle, contact with animals, age, and sex. A total of 288 stool samples were obtained from asymptomatic individuals over the entire age-range and 136 samples from animals with which the volunteers were in frequent contact. All samples were examined in parallel by PCR and xenic in vitro culture. Blastocystis sp. was detected in samples from both human and non-human hosts. In humans, the overall prevalence was 24% and eight subtypes were found; in animals, the prevalence was 10%, and only five subtypes were detected. A higher incidence of Blastocystis sp. was observed in individuals (i) traveling outside Europe, (ii) in frequent contact with livestock, and (iii) over 50 years of age. We found no effect on gender on Blastocystis sp. colonization.

Summary

This study provides data on the prevalence and diversity of the gut protist Blastocystis sp. and its subtypes in a gut-healthy human population with emphasis on several factors such as contact with animals, lifestyle, age, and gender.

PARV4 found in wild chimpanzee faeces: an alternate route of transmission?

Human parvovirus 4 (PARV4, family Parvoviridae, genus Tetraparvovirus) displays puzzling features, such as uncertain clinical importance/significance, unclear routes of transmission, and discontinuous geographical distribution. The origin, or the general reservoir, of human PARV4 infection is unknown. We aimed to detect and characterize PARV4 virus in faecal samples collected from two wild chimpanzee populations and 19 species of captive non-human primates. We aimed to investigate these species as a potential reservoir and alternate route of transmission on the African continent. From almost 500 samples screened, a single wild Pan troglodytes schweinfurthii sample tested positive. Full genome analysis, as well as single ORF phylogenies, confirmed species-specific PARV4 infection.

Adenovirus infection in savanna chimpanzees (Pan troglodytes schweinfurthii) in the Issa Valley, Tanzania

Adenoviruses are a widespread cause of diverse human infections with recently confirmed zoonotic roots in African great apes. We focused on savanna-dwelling chimpanzees in the Issa Valley (Tanzania), which differ from those from forested sites in many aspects of behavior and ecology. PCR targeting the DNA polymerase gene detected AdV in 36.7% (69/188) of fecal samples. We detected five groups of strains belonging to the species Human mastadenovirus E and two distinct groups within the species Human mastadenovirus C based on partial hexon sequence. All detected AdVs from the Issa Valley are related to those from nearby Mahale and Gombe National Parks, suggesting chimpanzee movements and pathogen transmission.

New adenoviruses from new primate hosts - growing diversity reveals taxonomic weak points

The knowledge of the closest human relatives of human adenoviruses (AdVs) such as adenoviruses found in nonhuman primates is still limited, despite the growing importance of adenoviruses in vaccine development, gene and cancer therapy. We examined 153 stool samples of 17 non-human primate species and detected adenoviral DNA sequences of DNA polymerase (DPOL) gene in 54 samples (35%), originating from 12 out of 17 primate species. We further sequenced 15 hexon gene fragments and based on the phylogenetic analysis we propose two new provisional species SAdV-H and SAdV-I. Our study shows extensive diversity of adenoviral strains forming separate clades often from closely related host species from old world monkeys suggesting the existence of new species of AdVs and shows the necessity for clear ICTV guidelines for final establishment of so far provisional AdV species.

A comparative molecular survey of malaria prevalence among Eastern chimpanzee populations in Issa Valley (Tanzania) and Kalinzu (Uganda)

BACKGROUND

Habitat types can affect vector and pathogen distribution and transmission dynamics. The prevalence and genetic diversity of Plasmodium spp. in two eastern chimpanzee populations-Kalinzu Forest Reserve, Uganda and Issa Valley, Tanzania-inhabiting different habitat types was investigated. As a follow up study the effect of host sex and age on infections patterns in Kalinzu Forest Reserve chimpanzees was determined.

METHODS

Molecular methods were employed to detect Plasmodium DNA from faecal samples collected from savanna-woodland (Issa Valley) and forest (Kalinzu Forest Reserve) chimpanzee populations.

RESULTS

Based on a Cytochrome-b PCR assay, 32 out of 160 Kalinzu chimpanzee faecal samples were positive for Plasmodium DNA, whilst no positive sample was detected in 171 Issa Valley chimpanzee faecal samples. Sequence analysis revealed that previously known Laverania species (Plasmodium reichenowi, Plasmodium billbrayi and Plasmodium billcollinsi) are circulating in the Kalinzu chimpanzees. A significantly higher proportion of young individuals were tested positive for infections, and switching of Plasmodium spp. was reported in one individual. Amongst the positive individuals sampled more than once, the success of amplification of Plasmodium DNA from faeces varied over sampling time.

CONCLUSION

The study showed marked differences in the prevalence of malaria parasites among free ranging chimpanzee populations living in different habitats. In addition, a clear pattern of Plasmodium infections with respect to host age was found. The results presented in this study contribute to understanding the ecological aspects underlying the malaria infections in the wild. Nevertheless, integrative long-term studies on vector abundance, Plasmodium diversity during different seasons between sites would provide more insight on the occurrence, distribution and ecology of these pathogens.

Novel CDKL5 Mutations in Czech Patients with Phenotypes of Atypical Rett Syndrome and Early-Onset Epileptic Encephalopathy

The X-linked CDKL5 gene, which encodes cyclin-dependent kinase-like 5 protein, has been implicated in early-onset encephalopathy and atypical Rett syndrome with early-onset seizures. The CDKL5 protein is a kinase required for neuronal development and morphogenesis, but its precise functions are still largely unexplored. Individuals with CDKL5 mutations present with severe global developmental delay, intractable epilepsy, and Rett-like features. A clear genotype-phenotype correlation has not been established due to an insufficient number of reported cases. The aim of this study was to analyse the CDKL5 gene in Czech patients with early-onset seizures and Rett-like features. We performed mutation screening in a cohort of 83 individuals using high-resolution melting analysis, DNA sequencing and multiplex ligation- dependent probe amplification. Molecular analyses revealed heterozygous pathogenic mutations in three girls with severe intellectual disability and intractable epilepsy starting at the age of two months. All three identified mutations, c.637G>A, c.902_977+29del105, and c.1757_1758delCT, are novel, thus significantly extending the growing spectrum of known pathogenic CDKL5 sequence variants. Our results support the importance of genetic testing of the CDKL5 gene in patients with early-onset epileptic encephalopathy and Rett-like features with early-onset seizures. This is the first study referring to molecular defects of CDKL5 in Czech cases.

Genetic and phylogenetic characterization of novel bocaparvovirus infecting chimpanzee

Primate bocaparvoviruses were first described in 2005, since then further human and gorilla bocaparvoviruses have been identified. To uncover diversity of non-human primates' bocaparvoviruses, their phylogenetic relationship and potential to cross the host species barrier, we tested 153 fecal samples from 17 captive primate species. The only one captive female of central chimpanzee (coded CPZh2) has been identified as bocaparvovirus positive. Based on the full genome phylogenetic analyses, CPZh2 strain shows close relationship to HBoV3 and GBoV. Further recombination analysis confirmed expected mosaic origin of CPZh2 strain. According the phylogenetic position, following the ICTV recommendations, we propose a novel genotype within the Primate bocaparvovirus 1 species infecting chimpanzee.

New species of Torque Teno miniviruses infecting gorillas and chimpanzees

Anelloviridae family is comprised of small, non-enveloped viruses of various genome lengths, high sequence diversity, sharing the same genome organization. Infections and co-infections by different genotypes in humans are ubiquitous. Related viruses were described in number of mammalian hosts, but very limited data are available from the closest human relatives - great apes and non-human primates. Here we report the 100% prevalence determined by semi-nested PCR from fecal samples of 16 captive primate species. Only the Mandrillus sphinx, showed the prevalence only 8%. We describe three new species of gorillas׳ and four new species of chimpanzees׳ Betatorqueviruses and their co-infections in one individual. This study is also first report and analysis of nearly full length TTMV genomes infecting gorillas. Our attempts to sequence the complete genomes of anelloviruses from host feces invariably failed. Broader usage of blood /tissue material is necessary to understand the diversity and interspecies transmission of anelloviruses.