Molecular Detection of the Carriage Rate of Four Intestinal Protozoa with Real-Time Polymerase Chain Reaction: Possible Overdiagnosis of Entamoeba histolytica in Nigeria

High Diversity of Giardia duodenalis Assemblages and Sub-Assemblages in Asymptomatic School Children in Ibadan, Nigeria

Giardia duodenalis is a significant contributor to the burden of diarrheal disease in sub-Saharan Africa. This study assesses the occurrence and molecular diversity of G. duodenalis and other intestinal parasites in apparently healthy children (n = 311) in Ibadan, Nigeria. Microscopy was used as a screening method and PCR and Sanger sequencing as confirmatory and genotyping methods, respectively. Haplotype analyses were performed to examine associations between genetic variants and epidemiological variables. At microscopy examination, G. duodenalis was the most prevalent parasite found (29.3%, 91/311; 95% CI: 24.3–34.7), followed by Entamoeba spp. (18.7%, 58/311; 14.5–23.4), Ascaris lumbricoides (1.3%, 4/311; 0.4–3.3), and Taenia sp. (0.3%, 1/311; 0.01–1.8). qPCR confirmed the presence of G. duodenalis in 76.9% (70/91) of the microscopy-positive samples. Of them, 65.9% (60/91) were successfully genotyped. Assemblage B (68.3%, 41/60) was more prevalent than assemblage A (28.3%, 17/60). Mixed A + B infections were identified in two samples (3.3%, 2/60). These facts, together with the absence of animal-adapted assemblages, suggest that human transmission of giardiasis was primarily anthroponotic. Efforts to control G. duodenalis (and other fecal-orally transmitted pathogens) should focus on providing safe drinking water and improving sanitation and personal hygiene practices.

Comparison of Three Real-Time PCR Assays Targeting the SSU rRNA Gene, the COWP Gene and the DnaJ-Like Protein Gene for the Diagnosis of Cryptosporidium spp. in Stool Samples

As qualified microscopy of enteric parasitoses as defined by high diagnostic accuracy is difficult to maintain in non-endemic areas due to scarce opportunities for practicing with positive sample materials, molecular diagnostic options provide less investigator-dependent alternatives. Here, we compared three molecular targets for the real-time PCR-based detection of Cryptosporidium spp. From a population of 1000 individuals comprising both Ghanaian HIV (human immunodeficiency virus) patients and military returnees after deployment in the tropics, stool samples were assessed for Cryptosporidium spp. by real-time PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene, the Cryptosporidium oocyst wall (COWP) gene, and the DnaJ-like protein gene (DnaJ), respectively. In declining order, sensitivity of 100% for the SSU rRNA gene PCR, 90.0% for the COWP PCR and 88.8% for the DnaJ PCR, respectively, as well as specificity of 99.6% for the COWP PCR and 96.9% for both the SSU rRNA gene PCR and the DnaJ PCR, respectively, were recorded. Substantial agreement (kappa value 0.663) between the three assays was observed. Further, an accuracy-adjusted Cryptosporidium spp. prevalence of 6.0% was calculated for the study population. In conclusion, none of the assessed real-time PCR assays were associated with perfect test accuracy. However, a combination of highly sensitive SSU rRNA gene PCR for screening purposes and more specific COWP PCR for confirmatory testing should allow reliable diagnosis of Cryptosporidium spp. in stool samples even in low prevalence settings.

Entamoeba species infection in patients seeking treatment for diarrhea and abdominal discomfort in Mukuru informal settlement in Nairobi, Kenya

Entamoeba histolytica is the only pathogenic species of the Entamoeba genus and is morphologically identical to E. dispar/E. moshkovskii (Entamoeba complex) hence cannot be microscopically differentiated. The other Entamoeba spp. found in humans (E. hartmanni, E. polecki, and E. coli) can be differentiated morphologically from this Entamoeba complex. However, some of their morphologic features overlap making differential diagnosis difficult. This study aimed at determining the occurrence of Entamoeba spp. in patients seeking treatment for diarrhea and/or abdominal discomfort at two clinics in Mukuru informal settlement in Nairobi, Kenya. Faecal samples were collected from 895 patients, examined microscopically following direct wet smear and formal-ether concentration methods. Entamoeba spp. positive faecal samples were subjected to DNA extraction and species-specific nested polymerase chain reaction of the 18S ribosomal RNA (rRNA). By microscopy, Entamoeba spp. cysts or trophozoites were detected in 114/895 (12.7%, 95% Confidence Interval (CI) 10.6-15.1) faecal samples. By nested PCR, the prevalence was: E. histolytica (7.5%, 95% CI 5.9-9.4, 67/895) and E. dispar (8.2%, 95% CI 6.5-10.2, 73/895). Among the Entamoeba spp. complex positive samples, nested PCR detected E. coli and E. hartmanni DNA in 63/114 (55.3%) and 37/114 (32.5%), samples respectively. Among the E. histolytica/E. dispar PCR negative samples (32.5%), 21 (18.4%) contained cysts of either E. coli (19) or E. hartmanni (2) by nested PCR. Entamoeba spp. infections were most common among participants aged 21-30 years; however it was not significant (P = 0.7). Entamoeba spp. infections showed an inverse relationship with diarrhea being most common among participants without diarrhea (P = 0.0). The difference was significant for E. histolytica (P = 0.0) but not significant for E. dispar (P = 0.1). Only E. dispar infections were significantly associated with sex (P = 0.0). This study highlights the need for differentiation of E. histolytica from other Entamoeba spp. by molecular tools for better management of amoebiasis.

High prevalence of intestinal parasite infestations among stunted and control children aged 2 to 5 years old in two neighborhoods of Antananarivo, Madagascar

BACKGROUND

This study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques.

METHODOLOGY/PRINCIPAL FINDINGS

Fecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2-5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques. A total of 96.3% of the children were infested with at least one intestinal parasite. The most prevalent parasites were Giardia intestinalis (79.5%), Ascaris lumbricoides (68.3%) and Trichuris trichiura (68.0%). For all parasites studied, real-time PCR showed higher detection rates compared to microscopy (G. intestinalis [77.6% (n = 318) versus 20.9% (n = 86)], Entamoeba histolytica [15.8% (n = 65) versus 1.9% (n = 8)] and A. lumbricoides [64.1% (n = 263) versus 50.7% (n = 208)]). Among the different variables assessed in the study, age of 4 to 5 years (AOR = 4.61; 95% CI, (1.35-15.77)) and primary and secondary educational level of the mother (AOR = 12.59; 95% CI, (2.76-57.47); AOR = 9.17; 95% CI, (2.12-39.71), respectively) were significantly associated with IPIs. Children drinking untreated water was associated with infestation with G. intestinalis (AOR = 1.85; 95% CI, (1.1-3.09)) and E. histolytica (AOR = 1.9; 95% CI, (1.07-3.38)). E. histolytica was also associated with moderately stunted children (AOR = 0.37; 95% CI, 0.2-0.71). Similarly, children aged between 4 and 5 years (AOR = 3.2; 95% CI (2.04-5.01)) and living on noncemented soil types (AOR = 1.85; 95% CI, (1.18-2.09)) were associated with T. trichiura infestation.

CONCLUSIONS/SIGNIFICANCE

The prevalence of IPIs is substantial in the studied areas in both stunted and control children, despite the large-scale drug administration of antiparasitic drugs in the country. This high prevalence of IPIs warrants further investigation. Improved health education, environmental sanitation and quality of water sources should be provided.

Review of zoonotic amebiasis: Epidemiology, clinical signs, diagnosis, treatment, prevention and control

Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica, which mainly shows symptoms of acute diarrhea, dysentery, amebic colitis, and amebic liver abscesses. As the fourth leading parasitic cause of human mortality, E. histolytica mainly infect children in developing countries, transmitted by food and water contamination. In the majority of infected individuals, Entamoeba sp. asymptomatically colonizes the large intestine and self-limiting, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Metronidazole (MTZ) is the recommended and most widely used drug for treating the invasive amebiasis. No amebiasis vaccine has been approved for human clinical trials to date, but many recent vaccine development studies hold promise. For the prevention and control of amebiasis, improvement of water purification systems and hygiene practices could decrease disease incidence. In this review, we focus on the epidemiology, transmission, clinical signs, pathogenesis, diagnosis, treatment, prevention and control of the zoonotic amebiasis.

The association between the lack of safe drinking water and sanitation facilities with intestinal Entamoeba spp infection risk: A systematic review and meta-analysis

Intestinal protozoa infections are responsible for considerable morbidity and mortality, especially where the exposed population suffers from a lack of drinking water and sanitation facilities. In this study, the association between the lack of safe drinking water and sanitation (toilet) facilities with intestinal Entamoeba spp infection in the children (5-11 years), adult (18-55 years), and all age (5-55 years) were assessed. For this purpose, some of the international databases such as Scopus, PubMed, Web of Science, and Embase were screened to up to 7 June 2019 in order to retrieve the related citations. Also, the pooled odds ratios (ORs) following 95% confidence intervals (CIs) were calculated using a random-effects model. Twenty-nine articles with 36 studies were included while the OR extracted or calculated by using 2 × 2 contingency tables. However, the ingestion of contaminated water insignificantly can increase the odds ratio (OR) of Entamoeba spp infection (OR 1.01, (95% confidence interval [CI] 0.58 to 1.43), no access to sanitation (toilet) facilities significantly can increase odds of Entamoeba spp infection (OR 1.18, 95% CI 1.05 to 1.32). The meta-regression analysis showed that over time, odds of intestinal Entamoeba spp infection increased in both lack of safe drinking water (Coefficient: 3.24, P-value < 0.01) and sanitation (toilet) facilities (Coefficient: 2.36, P-value < 0.05) subgroups. Considering the findings, lack of safe drinking water resulted in a further increase in intestinal Entamoeba spp infection among adult (OR: 2.76), children (OR = 0.57) and all age groups (OR: 1.50), and also lack of sanitation (toilet) facilities resulted in further increase intestinal Entamoeba spp infection in children (OR: 1.06), adult (OR: 1.26) and all age (OR: 1.16). In this context, the lack of safe drinking water and sanitation facilities (toilet) was associated with a high risk of intestinal Entamoeba spp infection. Further attempts to providing public health facilities can control the prevalence of intestinal Entamoeba spp.

Surveillance of enteropathogenic bacteria, protozoa and helminths in travellers returning from the tropics

Diarrhoea is a frequent symptom associated with travelling to tropical regions, but the cause is often not found. Epidemiology was assessed including up-to-date real-time PCR approaches.We analysed datasets of 528 patients who presented at the Bernhard Nocht Institute for Tropical Medicine in Hamburg, Germany, between 2006 and 2010 for screening purposes or because of diarrhoea. Stool samples were obtained and investigated by microscopy, bacterial culture, two PCR assays targeting Entamoeba histolytica, Entamoeba dispar, Giardia duodenalis, and Cryptosporidium parvum, or Salmonella spp., Shigella/EIEC spp., Campylobacter jejuni, and Yersinia spp.Among patients with gastrointestinal symptoms, 51% tested positive for bacteria or parasites, of which 66% had a known enteropathogenic potential. In patients without diarrhoea, 53% (n = 80) were positive, and 33% of these cases harboured agents of pathogenic potential. Association with clinical symptoms was primarily found for bacterial infections. Blastocystis hominis, however, was more frequent in asymptomatic than in symptomatic travellers.In conclusion, the study stresses the etiological relevance of bacterial gastroenteritis in travellers returning from the tropics, the need for molecular approaches to increase diagnostic sensitivity and demonstrates that asymptomatic carriage of enteropathogens after prolonged stays in the tropics is similarly frequent compared with symptomatic infections in travellers.

High Prevalence of Intestinal Pathogens in Indigenous in Colombia

Background: Intestinal infections remain a major public health burden in developing countries. Due to social, ecological, environmental, and cultural conditions, Indigenous peoples in Colombia are at particularly high risk. Materials: 137 stool samples were analyzed by microscopy and real-time-Polymerase Chain Reaction (RT-PCR), targeting protozoan parasites (Giardia intestinalis, Entamoeba histolytica, Cryptosporidium spp., and Cyclospora cayetanensis), bacteria (Campylobacter jejuni, Salmonella spp., Shigella ssp./enteroinvasive E. coli (EIEC), Yersinia spp., enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), enterotoxin-producing E. coli (ETEC), enteroaggregative E. coli (EAEC), and Tropheryma whipplei), and helminths (Necator americanus, Strongyloides stercoralis, Ascaris lumbricoides, Ancylostoma spp., Trichuris. trichiura, Taenia spp., Hymenolepis nana, Enterobius vermicularis, and Schistosoma spp.). Microscopy found additional cases of helminth infections. Results: At least one pathogen was detected in 93% of the samples. The overall results revealed protozoa in 79%, helminths in 69%, and bacteria in 41%. G. intestinalis (48%), Necator/hookworm (27%), and EAEC (68%) were the most common in each group. Noteworthy, T. whipplei was positive in 7% and T. trichirua in 23% of the samples. A significant association of one infection promoting the other was determined for G. intestinalis and C. jejuni, helminth infections, and EIEC. Conclusions: The results illustrate the high burden of gastrointestinal pathogens among Indigenous peoples compared to other developing countries. Countermeasures are urgently required.

Risk associations for intestinal parasites in symptomatic and asymptomatic schoolchildren in central Mozambique

OBJECTIVES

Chronic infections by enteric parasites including protist and helminthic species produce long-term sequelae on the health status of infected children. This study assesses potential associations linked with enteric parasite infections in symptomatic and asymptomatic children in Zambézia province, Mozambique.

METHODS

In this prospective cross-sectional study, stool samples and epidemiological questionnaires on demographics and risk associations were collected from symptomatic children (n = 286) from clinical settings and asymptomatic (n = 807) children from 17 schools and creches aged 3‒14 years. We detected enteric parasites using PCR-based methods. We calculated prevalence (adjusted for age, sex, house construction, drinking water, and latrine use) and odds ratios (ORs) for risk associations with logistic regression, after adjusting for district, neighbourhood and symptoms.

RESULTS

Numbers and adjusted prevalence (95% confidence intervals in parentheses) for the symptomatic and asymptomatic populations were Giardia duodenalis 120, 52% (22-82), 339, 42% (25-59); followed by Strongyloides stercoralis 52, 14% (9‒20), 180, 20% (15-25). Risk associations for G. duodenalis included drinking untreated river/spring water, OR 2.91 (1.80-4.70); contact with ducks, OR 14.96 (2.93‒76.31); dogs, OR 1.92 (1.04-3.52); cats, OR 1.73 (1.16-2.59), and a relative with diarrhoea, OR 2.59 (1.54‒4.37). Risk associations for S. stercoralis included having no latrine, OR 2.41 (1.44-4.02); drinking well water, OR 1.82 (1.02-3.25), and increasing age, OR 1.11 (1.04-1.20).

CONCLUSIONS

We found a high prevalence of intestinal parasites regardless of the children's symptoms. Drinking well or river water, domestic animals, and latrine absence were contributing factors of human infections.

Molecular epidemiology, evolution, and phylogeny of Entamoeba spp

Entamoeba histolytica is a protozoan parasite and the causative agent of amoebiasis in humans. The estimations of the worldwide burden of amoebiasis by the WHO indicated that approximately 500 million people were infected with the parasite and 10% of these individuals had invasive amoebiasis. However, our understanding of the disease burden and epidemiology of human amebiasis has undergone dramatic changes over the last two decades based on molecular analyses. The development of Entamoeba genomics has also provided some interesting and valuable information on the evolution and population structure of this parasite. In addition, the use of a number of molecular markers has greatly expanded our understanding of Entamoeba host range and genetic diversity. In this review, we re-assessed Entamoeba prevalence and species in humans, non-human primates, other animals, and the environment in the context of molecular data. Some issues regarding the evolution and phylogeny of different Entamoeba species lineages are also discussed.

Multi-locus genotyping and phylogenetic analyses of Giardia intestinalis isolates from indigenous goats in Ogun State, Nigeria

Giardiasis is a common gastrointestinal disease of humans and various animal species worldwide. In this study, 302 stool samples were collected from West African Dwarf and Sokoto Red breeds of goats in Ogun State, Nigeria, and screened for Giardia intestinalis coproantigens using enzyme-linked immunosorbent assay (ELISA). The genotypes of G. intestinalis in faecal samples collected from 152 goats raised on selected farms were identified by polymerase chain reaction (PCR) amplification and sequence analyses of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and β-giardin (bg) genes. Based on ELISA, an overall prevalence of 45.7% was recorded with the infection rates in pre-weaned (60.2%) and post-weaned goat kids (51.5%) being significantly (p < 0.05) higher than in adults (28.2%). Giardia intestinalis DNA was amplified in 31.6% and 29.6% of goat faeces at the ssu rRNA and gdh loci respectively. These were genotyped at the ssu rRNA locus as assemblages B (n = 13) and E (n = 36). Similar results were observed at the gdh locus except that eight isolates contained assemblage E mixed with either assemblage A or B. Additionally, sub-assemblages BI (n = 7) and BIII (n = 2) were identified with up to four single nucleotide polymorphisms (SNPs) occurring in these isolates. Multilocus genotypes (MLG) of all assemblage E isolates were identified using the ssu rRNA and gdh loci while MLG of all isolates containing assemblage B and mixed assemblages were determined after further typing at the tpi and bg loci. Forty-two MLG isolates were identified and these comprised 32, 8 and 2 (sub)-assemblage E, BI and BIII respectively. All isolates with mixed assemblages at the gdh locus were consequently designated as assemblage E by MLG. The assemblage E isolates from goats were genetically related to isolates from cattle, sheep and goats while the assemblage B isolates were related to isolates of human, pig and lemur origin. This suggests that G. intestinalis isolated from goats bred in Ogun State, Nigeria may be capable of cross-species transmission and may be of zoonotic importance.

Prevalence and multilocus genotypes of Giardia duodenalis infecting pigs in Ogun state, Nigeria

Giardia duodenalis is an intestinal flagellated protozoan parasite that is infectious to humans and a wide range of animals worldwide. While varying prevalence rates have been reported in pigs worldwide, there are currently no published reports on the genotypes of Giardia infecting pigs in any African country. The present study is on the prevalence and genotypes of G. duodenalis in 209 pigs raised on four farms in Ogun State Nigeria. Using an enzyme-linked immunosorbent assay (ELISA) kit, Giardia duodenalis coproantigens were detected on all farms and in 25.4% (53/209) of pigs sampled. However, there was no significant influence (p > 0.05) of age, sex and stool consistencies of the pigs on the distribution of the infection. Genotyping of Giardia duodenalis in all ELISA-positive samples, achieved by the amplification of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta giardin (bg) genes, identified 14 and 37 assemblage B and E isolates respectively while mixed infection by both assemblages was recorded in two isolates. Novel nucleotide substitutions were identified in four assemblage B isolates at the ssu rRNA locus. Genetic diversity was observed among the assemblage B isolates after multiple alignment analyses of the gdh, tpi and bg sequences whereby sub-assemblages BII (n = 2), BIII (n = 9) and BIV (n = 3) were identified. The assemblage B isolates from pigs in this study were phylogenetically related to isolates from humans, marmoset and cattle while the assemblage E isolates were related to isolates from sheep, goats and cattle. These findings suggest that pigs in southwest Nigeria predominantly harbour G. duodenalis isolates that could be infectious to other animal species and to a lesser extent, isolates that may be of zoonotic importance.

Development and evaluation of molecular tools for detecting and differentiating intestinal amoebae in healthy individuals

Amoebae are single-celled parasites frequently colonizing human gut. However, few molecular tools are available for accurate identification. Here, we evaluated a panel of polymerase chain reactions (PCRs) targeting Entamoeba histolytica, Entamoeba dispar, Entamoeba coli, Entamoeba hartmanni, Entamoeba polecki, Endolimax nana and Iodamoeba bütschlii. Thirty-six faecal samples (18 containing at least one amoeba species by microscopy and 18 microscopy negative for amoebae) were tested. Real-time PCRs were used for detection and differentiation of E. histolytica and E. dispar. Conventional PCR with Sanger sequencing were applied for detection and differentiation of E. coli, E. hartmanni, E. polecki, E. nana and I. bütschlii. All microscopy results were confirmed by DNA-based methods. However, more samples were positive for single and mixed amoebic species by DNA-based assays than by microscopy (22 vs 18 and 7 vs 1, respectively). DNA sequencing allowed identification of E. coli subtypes (ST1 and ST2), showed low intra-specific variation within E. hartmanni, identified two phylogenetically distinct groups within E. nana, and identified Iodamoeba at the ribosomal lineage level. Taking into account the high intra-genetic diversity within some of the species at the small subunit (SSU) rRNA gene level, amplification of SSU rRNA genes with subsequent sequencing represents a useful method for detecting, differentiating and subtyping intestinal amoebae.

Apparent absence of Giardia infections among children under 5-years of age with acute watery diarrhoea in Abakaliki, Nigeria

Although the impact of diarrhoeal disease on paediatric health in Nigeria has decreased in recent years, it remains an important cause of morbidity and mortality in children under 5 years. Rotavirus is recognised as an important aetiological agent, but information on the contribution of intestinal protozoa to watery diarrhoea in this age group in Nigeria is scarce. In this cross-sectional study, faecal samples from children admitted to healthcare centres in Abakaliki, Nigeria with acute watery diarrhoea (N = 199) and faecal samples from age-matched controls (N = 37) were examined for Cryptosporidium and Giardia using immunofluorescent antibody testing and molecular methods. Cryptosporidium was identified in 13 case samples (6.5%) and no control samples. For three samples, molecular characterisation indicated C. hominis, GP60 subtypes IaA30R3, IaA14R3 and IdA11. Giardia was not detected in any samples. This contrast in prevalence between the two intestinal protozoa may reflect their variable epidemiologies and probably differing routes of infection. Given that these two parasitic infections are often bracketed together, it is key to realise that they not only have differing clinical spectra but also that the importance of each parasite is not the same in different age groups and/or settings.

Multilocus genotyping of Giardia duodenalis infecting rabbits in Ogun State, Nigeria

Giardiasis is a cosmopolitan gastrointestinal protozoal parasite that infects humans and various animals worldwide. To assess the zoonotic transmission potential of Giardia, molecular characterization is required. We are unaware of any report on the genotypes of Giardia infecting rabbits in Nigeria. Molecular detection and genotyping of Giardia duodenalis were conducted in a herd of adult Chinchilla rabbits (Oryctolagus cuniculus) managed on the Teaching and Research farm of the Federal University of Agriculture, Abeokuta located in a southwestern state of Nigeria by analysis of the small-subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and beta-giardin (bg) genes. An overall prevalence of 72.3% (60/83) was recorded in the rabbits with no statistically significant (p > .05) influence of sex on the distribution of the infection in the herd. All the 19 isolates amplified at the four genetic loci were identified as G. duodenalis assemblage BIV by multiple alignment analysis of their consensus sequences. Novel nucleotide substitutions were identified in two isolates at the ssu rRNA locus. Phylogenetic analysis revealed that all ssu rRNA genotypes were closely related to G. duodenalis assemblage B of cattle and human origin. Findings of this study suggest that the rabbits harbour potentially zoonotic assemblage BIV that portends a high risk to students and staff of the University who are in regular contact with the animals.

Phytochemical and Pharmacological Review of Cryptolepis sanguinolenta (Lindl.) Schlechter

Ethnopharmacological Relevance

Cryptolepis sanguinolenta is a scrambling thin-stemmed shrub found in Africa. Traditionally in West Africa, it is employed in the treatment of malaria, diarrhea, and respiratory conditions. This review discusses the traditional importance as well as the phytochemical, ethnomedical, pharmacological, and toxicological importance of this plant.

Materials and Methods

Excerpta Medica Database, Google Scholar, Springer, and PubMed Central were the electronic databases used to search for and filter primary studies on Cryptolepis sanguinolenta.

Results

The detailed review of various studies conducted on C. sanguinolenta and some of its constituents gives an important body of proof of its potential therapeutic benefits and also of its use as a source of lead compounds with therapeutic potentials.

Conclusion

The review on C. sanguinolenta is important in identifying grey areas in the research on this medicinal plant and also provides comprehensive data thus far to continue research on this plant.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Diagnosing Polyparasitism in a High-Prevalence Setting in Beira, Mozambique: Detection of Intestinal Parasites in Fecal Samples by Microscopy and Real-Time PCR

BACKGROUND

Many different intestinal parasite species can co-occur in the same population. However, classic diagnostic tools can only frame a particular group of intestinal parasite species. Hence, one or two tests do not suffice to provide a complete picture of infecting parasite species in a given population. The present study investigated intestinal parasitic infections in Beira, Mozambique, i.e. in the informal settlement of Inhamudima. Diagnostic accuracy of five classical microscopy techniques and real-time PCR for the detection of a broad spectrum of parasites was compared.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional population-based survey was performed. One stool sample per participant (n = 303) was examined by direct smear, formal-ether concentration (FEC), Kato smear, Baermann method, coproculture and real-time PCR. We found that virtually all people (96%) harbored at least one helminth, and that almost half (49%) harbored three helminths or more. Remarkably, Strongyloides stercoralis infections were widespread with a prevalence of 48%, and Ancylostoma spp. prevalence was higher than that of Necator americanus (25% versus 15%), the hookworm species that is often assumed to prevail in East-Africa. Among the microscopic techniques, FEC was able to detect the broadest spectrum of parasite species. However, FEC also missed a considerable number of infections, notably S. stercoralis, Schistosoma mansoni and G. intestinalis. PCR outperformed microscopy in terms of sensitivity and range of parasite species detected.

CONCLUSIONS/SIGNIFICANCE

We showed intestinal parasites-especially helminths-to be omnipresent in Inhamudima, Beira. However, it is a challenge to achieve high diagnostic sensitivity for all species. Classical techniques such as FEC are useful for the detection of some intestinal helminth species, but they lack sensitivity for other parasite species. PCR can detect intestinal parasites more accurately but is generally not feasible in resource-poor settings, at least not in peripheral labs. Hence, there is a need for a more field-friendly, sensitive approach for on-the-spot diagnosis of parasitic infections.

Epidemiological Aspects of Blastocystis Colonization in Children in Ilero, Nigeria

This study aimed to elucidate aspects of the epidemiology of Blastocystis in Nigerian school children, including the distribution of subtypes (STs) and ST alleles. A total of 199 genomic DNAs extracted from fecal samples from 199 Nigerian children aged 2-14 years were tested by real-time polymerase chain reaction for Blastocystis Positive DNAs were submitted to barcoding by PCR and sequencing to obtain information on STs and ST alleles. A total of 167 (84%) samples were positive for Blastocystis, with prevalence increasing by age. No association between Blastocystis colonization and gender (P = 0.51) or type/presence of toilet facilities (P = 0.21) was observed. Blastocystis carriers were more prone to using water collected from wells than from sachets (P = 0.0044). Moreover, Blastocystis positivity was associated with positivity for fecal-orally transmitted protozoa (P = 0.018) and helminths (P < 0.0001). A clear inverse association of Blastocystis colonization and malaria infection was observed (P < 0.0001); however, malaria-positive children being younger than malaria-negative children, this finding was attributed to the age effect of Blastocystis colonization. ST data were available for 127/167 (76%) samples. Fifty-one children were positive for ST1, while 42 and 33 children were colonized with ST2 and ST3, respectively; a single case of ST7 was observed. By and large, the ST alleles identified for ST1 and ST2 did not differ from those observed in humans in other regions of the world; meanwhile, the distribution of ST3 alleles was remarkably distinct and potentially specific to humans in sub-Saharan Africa.

Frequency and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, and Entamoeba hartmanni in the context of water scarcity in northeastern Brazil

This study aimed to estimate the frequency, associated factors, and molecular characterisation of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, andEntamoeba hartmanni infections. We performed a survey (n = 213 subjects) to obtain parasitological, sanitation, and sociodemographic data. Faecal samples were processed through flotation and centrifugation methods.E. histolytica, E. dispar, E. moshkovskii, and E. hartmanni were identified by nested-polymerase chain reaction (PCR). The overall prevalence of infection was 22/213 (10.3%). The infection rate among subjects who drink rainwater collected from roofs in tanks was higher than the rate in subjects who drink desalinated water pumped from wells; similarly, the infection rate among subjects who practice open defecation was significantly higher than that of subjects with latrines. Out of the 22 samples positive for morphologically indistinguishableEntamoeba species, the differentiation by PCR was successful for 21. The species distribution was as follows: 57.1% to E. dispar, 23.8% to E. histolytica, 14.3% toE. histolytica and E. dispar, and 4.8% E. dispar and E. hartmanni. These data suggest a high prevalence of asymptomatic infection by the group of morphologically indistinguishable Entamoeba histolytica/dispar/moshkovskiicomplex and E. hartmanni species. In this context of water scarcity, the sanitary and socioenvironmental characteristics of the region appear to favour transmission.

Cell-Free DNA as a Diagnostic Tool for Human Parasitic Infections

Parasites often cause devastating diseases and represent a significant public health and economic burden. More accurate and convenient diagnostic tools are needed in support of parasite control programmes in endemic regions, and for rapid point-of-care diagnosis in nonendemic areas. The detection of cell-free DNA (cfDNA) is a relatively new concept that is being applied in the current armamentarium of diagnostics. Here, we review the application of cfDNA detection with nucleic acid amplification tests for the diagnosis and evaluation of different human parasitic infections and highlight the significant benefits of the approach using non-invasive clinical samples.