Prevalence of Giardia intestinalis Infection in Schistosomiasis-Endemic Areas in South-Central Mali

Intestinal parasite infections are frequent causes of diarrhea and malnutrition among children in the tropics. Transmission of helminths and intestinal protozoa is intimately connected with conditions of poverty, including inadequate sanitation and hygiene. Concurrent infections with several intestinal pathogens may lead to excess morbidity. Yet, there is a paucity of epidemiological data from Mali. In this study, stool samples from 56 individuals, aged 2–63 years, from Bamako and Niono, south-central Mali were examined for intestinal parasites using stool microscopy. Additionally, stool samples were subjected to a rapid diagnostic test (RDT) and polymerase chain reaction (PCR) for the detection of Cryptosporidium spp. and Giardia intestinalis. The predominant pathogens were Schistosoma mansoni and G. intestinalis with prevalences of 41% and 38%, respectively. Hymenolepis nana was detected in 4% of the participants, while no eggs of soil-transmitted helminths were found. Concurrent infections with G. intestinalis and S. mansoni were diagnosed in 16% of the participants. For the detection of G. intestinalis, PCR was more sensitive (100%) than RDT (62%) and microscopy (48%). As helminth-protozoa coinfections might have important implications for morbidity control programs, future studies should employ diagnostic tools beyond stool microscopy to accurately assess the co-endemicity of giardiasis and schistosomiasis

Epidemiology and clinical features of Clostridioides difficile-associated diarrhoea and intestinal parasitic infections in Mali

Background: Although Clostridioides difficile is nowadays considered one of the most important diarrheal pathogens worldwide, with a high mortality and significant impact on the health care system, few data are available on the epidemiology and clinical burden of C. difficile in lower-income countries of the global South. Diarrheal diseases are of considerable relevance in many African countries, as they give rise to high morbidity and mortality. Because adequate laboratory diagnostics are often unavailable in less developed countries, the aetiology of diarrheal diseases remains frequently unclear. Recent studies from African countries indicate that C. difficile should also be considered as a possible differential diagnosis for diarrheal diseases. There is also an ongoing debate on a possible zoonotic route of transmission via close animal contact and animal products. Methode: A case-control study was conducted between February and April 2016 to analyse the prevalence of C. difficile in patients with diarrhea, asymptomatic controls, and animal samples in Mali. A total of 333 stool samples were acquired in Bamako and Niono, with 233 samples of human origin from hospitals and healthcare centers. Another 100 samples were collected from animals at local livestock markets. A rapid diagnostic test (RDT) detecting the C. difficile-specific glutamic dehydrogenase (GDH) and toxins A and B, an anaerobic stool culture, and a polymerase chain reaction (PCR) test were performed on-site in Bamako. Study participants also answered a questionnaire to detect possible risk factors for C. difficile infection. All positive samples were transferred to Homburg for susceptibility testing and further ribotyping. Additionally, stool samples were examined on site for parasites using the Kato-Katz method and microscopic direct detection. Kato-Katz and microscopic direct detection were assessed for diagnostic agreement. Results: Using the rapid test for detection of pathogen-specific GDH, the prevalence of C. difficile in humans was 7.2% in Bamako (13/180 samples) and 0% in Niono (0/53 samples). Among the 100 samples of animal origin, only one sample originating from a chicken was positive. Among the positive samples, the rapid test for C. difficile-specific toxins was negative in all human samples but positive in the animal sample. Further PCR testing of the positive samples in Mali showed toxins A and B in the animal sample and in three other human samples. In Mali, no binary toxin could be detected in any sample. The PCR in Homburg, in contrast, showed identical results for the positive animal sample, but found only one toxigenic human sample positive for toxins A and B and the binary toxin. Ribotypes previously described in the literature were identified in 9 cases, with RT084 being the most frequently detected. RT078 and RT012 were also found, and four samples belonged to previously undescribed ribotypes. Antibiotic resistance was found only against clarithomycin (9/13, 69%). There was no significant association between general risk factors such as age, antibiotic therapy, and hospitalization, with C. difficile infection. However, a correlation between the occurrence of diarrhea and the detection of C. difficile was found (n= 2, 16.6% p=0.007). The most common helminths were Dicrocoelium dendriticum in Bamako (9/180, 5.0%) and Schistosoma mansoni in Niono (34/53, 64.2%) Conclusion: C. difficile was detected in both human and animal samples from Mali. Simple and inexpensive screening tests, such as the GDH test, can contribute to detection of C. difficile infection even in resource-limited settings. Parasitic diseases should be considered as an important differential diagnosis of diarrhea in the tropics. Further studies are needed to assess the true importance of C. difficile as a disease-causing pathogen in Mali.Hintergrund: Obwohl Clostridioides difficile heute weltweit als einer der wichtigsten Durchfallerreger mit einer hohen Sterblichkeit und bedeutenden Auswirkungen auf das Gesundheitssystem gilt, liegen wenig Daten zur Epidemiologie und dem klinischen Stellenwert von C. difficile in ärmeren Ländern des globalen Südens vor. Durchfallerkrankungen sind in vielen afrikanischen Ländern von erheblicher Relevanz, da sie häufig mit einer hohen Morbidität und Mortalität verbunden sind. Weil eine adäquate Labordiagnostik in wenig entwickelten Ländern meist fehlt, bleibt die Ätiologie von Durchfallerkrankungen häufig unklar. Aktuelle Studien aus afrikanischen Ländern zeigen, dass C. difficile auch dort als mögliche Differentialdiagnose für Durchfallerkrankungen in Betracht gezogen werden sollte. Zunehmend wird auch ein möglicher zoonotischer Übertragungsweg über engen Tierkontakt und tierische Produkte diskutiert. Methoden: Zwischen Februar und April 2016 wurde eine Fall-Kontroll-Studie durchgeführt, um die Prävalenz von C. difficile bei Patienten mit Durchfall, asymptomatischen Kontrollen sowie Tierproben in Mali zu analysieren. In Bamako und Niono wurden insgesamt 333 Stuhlproben akquiriert, wobei 233 Proben humanen Ursprungs waren und aus Krankenhäusern und Gesundheitszentren stammten. Weitere 100 Proben wurden von Nutztieren auf lokalen Viehmärkten gesammelt. Ein diagnostischer Schnelltest (RDT), der eine C. difficile-spezifische Glutamatdehydrogenase (GDH) und die Toxine A und B nachweist, eine anaerobe Stuhlkultur und ein Polymerase-Kettenreaktionstest (PCR) wurden vor Ort in Bamako durchgeführt. Die Studienteilnehmer beantworteten zusätzlich einen Fragebogen, um mögliche Risikofaktoren für eine C. difficile Infektion zu detektieren. Alle positiven Proben wurden nach Homburg für Empfindlichkeitstests und zur weiteren Ribotypisierung transferiert. Weiterhin wurden vor Ort in Mali Stuhlproben mittels der Kato-Katz Methode und mikroskopischem Direktnachweis auf Parasiten untersucht. Kato-Katz und der mikroskopische Direktnachweis wurden bezüglich ihrer diagnostischen Übereinstimmung beurteilt. Ergebnisse: Unter Verwendung des Schnelltests zum Nachweis der pathogen-spezifischen GDH betrug die Prävalenz von C. difficile beim Menschen 7,2 % in Bamako (13/180 Proben) und 0 % in Niono (0/53 Proben). Unter den 100 Proben tierischen Ursprungs war nur eine einzige von einem Huhn stammende Probe positiv. Bei den positiven Proben war der Schnelltest für C. difficile-spezifische Toxine in allen humanen Proben negativ, in der tierischen Probe jedoch positiv. Die weitere PCR-Untersuchung der positiven Proben in Mali zeigte in der Tierprobe sowie in drei weiteren humanen Proben die Toxine A und B. In Mali konnte in keiner Probe ein binäres Toxin nachgewiesen werden. Im Gegensatz dazu ergab die PCR in Homburg identische Ergebnisse für die positive Tierprobe, fand aber nur eine toxigene Humanprobe, die positiv für die Toxine A und B sowie das binäre Toxin war. Zuvor in der Literatur beschriebene Ribotypen konnten in 9 Fällen identifiziert werden, wobei RT084 am häufigsten nachgewiesen wurde. RT078 und RT012 wurden ebenfalls gefunden, vier Proben gehörten zu bisher unbeschriebenen Ribotypen. Antibiotika-Resistenzen fanden sich nur gegenüber Clarithomycin (9/13, 69%). Es bestand kein signifikanter Zusammenhang zwischen allgemeinen Risikofaktoren wie Alter, Antibiotikatherapie und Krankenhausaufenthalt und einer C. difficile-Infektion. Ein Zusammenhang zwischen dem Vorliegen einer Diarrhoe und dem Nachweis von C. difficile konnte gezeigt werden (n= 2, 16,6%, p=0,007). Die häufigsten Helminthen waren Dicrocoelium dendriticum in Bamako (9/180, 5,0%) und Schistosoma mansoni in Niono (34/53; 64,2%) Schlussfolgerung C. difficile konnte in Mali sowohl in humanen Proben als auch in einer Tierprobe nachgewiesen werden. Einfache und günstige Screeningtests, wie beispielsweise der GDH-Test, können zu Detektion einer C. difficile Infektion auch in ressourcenlimitierten Settings beitragen. Als wichtige Differentialdiagnose des Durchfalls sollten in Mali parasitäre Erkrankungen in Betracht gezogen werden. Um den tatsächlichen Stellenwert von C. difficile als krankheitserregendes Pathogen in Mali bewerten zu können, bedarf es weiterer Studien

Prevalence of <i>Giardia intestinalis</i> Infection in Schistosomiasis-Endemic Areas in South-Central Mali

Intestinal parasite infections are frequent causes of diarrhea and malnutrition among children in the tropics. Transmission of helminths and intestinal protozoa is intimately connected with conditions of poverty, including inadequate sanitation and hygiene. Concurrent infections with several intestinal pathogens may lead to excess morbidity. Yet, there is a paucity of epidemiological data from Mali. In this study, stool samples from 56 individuals, aged 2&#8722;63 years, from Bamako and Niono, south-central Mali were examined for intestinal parasites using stool microscopy. Additionally, stool samples were subjected to a rapid diagnostic test (RDT) and polymerase chain reaction (PCR) for the detection of Cryptosporidium spp. and Giardia intestinalis. The predominant pathogens were Schistosoma mansoni and G. intestinalis with prevalences of 41% and 38%, respectively. Hymenolepis nana was detected in 4% of the participants, while no eggs of soil-transmitted helminths were found. Concurrent infections with G. intestinalis and S. mansoni were diagnosed in 16% of the participants. For the detection of G. intestinalis, PCR was more sensitive (100%) than RDT (62%) and microscopy (48%). As helminth-protozoa coinfections might have important implications for morbidity control programs, future studies should employ diagnostic tools beyond stool microscopy to accurately assess the co-endemicity of giardiasis and schistosomiasis