Is there added value from using three serial samples when surveying the occurrence of intestinal parasites in children?

BACKGROUND: Surveys for intestinal parasitic infections (IPIs) often involve samples from three sampling dates analysed by various microscopy techniques. However, analysis of three samples per individual is a huge burden on time and resources. We compared the value from analysing three or fewer samples. METHODS: In this cross-sectional study, three faecal samples were collected every other day from 332 children from two locations in Guantanamo province, Cuba. Samples were analysed by wet mount with Lugol stain, Willis flotation method and Kato-Katz thick smear. RESULTS: Most parasites were detected by wet mount, although helminth eggs not found by wet smear were detected by the Willis flotation method (in particular) and Kato-Katz smear. Blastocystis spp. was the most commonly detected parasite (about 65%), then Giardia duodenalis and then Entamoeba spp. Although analysis of two stool samples significantly increased occurrence data for Blastocystis, this was not so for the other parasites. For none of the protozoan parasites were results from analysing three samples significantly higher than results from analysing just two samples. CONCLUSIONS: Analysing two faecal samples by wet mount and the Willis flotation method provides useful data for estimating the prevalence of IPIs in relatively high prevalence settings. Analysing further samples provides limited additional information and adds an extra burden in terms of time and resources.

Identification of two potential aetiological agents of chronic diarrhoea in an immunocompromised patient in Cuba using conventional and molecular diagnostic techniques.

The aetiology of diarrhoea in a patient in Cuba with HIV was investigated. Although molecular diagnostics are still not used in many under-resourced settings, here traditional methods were supported by use of PCR. This approach enabled detection of a dual infection (Cystoisospora belli and Enterocytozoon bieneusi), the latter of which was not identified by microscopy with Didier's trichromic staining.

A retrospective study of Taenia spp. in Cuban patients: what does molecular analysis tell us?

Taeniosis is a neglected disease, particularly in developing countries, and is caused by infection with the adult tapeworm of either Taenia solium, Taenia saginata, and Taenia asiatica. Of these, T. solium is of primary concern due to the potential for cysticercosis should T. solium eggs be ingested. In Cuba, all cases of taeniosis are assumed to be caused by T. saginata, although some cases of cysticercosis have been documented. It is therefore important to gain further insights regarding the species causing taeniosis in Cuba, especially as diagnostic records indicate an increasing incidence, with the highest number of cases reported in 2020. In this study, we analysed 37 Taenia-positive faecal samples (or proglottids isolated from faecal samples) from the period 2001 until 2020 from all regions of the country. Genomic DNA was extracted from the samples, which had been stored in 10% formalin, using the QIAamp Tissue Kit. Species identification was carried out by duplex real-time PCR targeting the mitochondrial DNA. All cases were found to be T. saginata, and sequence analysis of three isolates confirmed the identification of this species. Our data do not provide any evidence that T. solium currently occurs in Cuba. However, given the relatively low number of samples analysed here, that the parasite may be imported with visitors or travellers who have been in endemic countries, and that taeniosis has relatively mild symptoms and thus infected patients may not seek medical attention, we recommend species determination for all taeniosis cases reported in Cuba.

Frecuencia de infección por cestodos en el Laboratorio Nacional de Referencia de Parasitismo Intestinal-IPK, Cuba, 2010-2018 / Frequency of cestode infection at the Intestinal Parasitic Disease National Reference Laboratory of Pedro Kourí Institute in Cuba, 2010-2018

Introdución: Los cestodos son helmintos parásitos del humano y de animales, con complejos ciclos de vida. En las infecciones por los cestodos no existen programas de desparasitación masiva implementados para disminuir la carga parasitaria de estos a nivel mundial, dada la baja prevalencia que se informa en estudios epidemiológicos. Existen pocos trabajos sobre la epidemiología y la detección de estas infecciones en la literatura internacional. Objetivo: Describir la frecuencia de infección de cestodos y sus características epidemiológicas. Métodos: Estudio descriptivo y retrospectivo, realizado entre el 3 de enero de 2010 y 28 de diciembre de 2018. Se analizaron todas las muestras de heces, parásitos adultos y metacestodos enviadas de la red de Salud al Laboratorio Nacional de Referencia de Parasitismo Intestinal-IPK. El universo de estudio estuvo constituido por 9833 muestras, que fueron enviadas mayoritariamente de la provincia La Habana. Resultados: La infección por Inermicapsifer madagascariensis predominó en niños menores de 5 años (69,6 por ciento; IC 95 por ciento: 47,1-86,8). La infección intestinal por Taenia spp. se diagnosticó prinipalmente en pacientes entre 15 y 65 años de edad (88,2 por ciento; IC95 por ciento: 63,6-98,5). De los 47 casos positivos a la infección por cestodos, 24 pertenecieron al sexo femenino (51,1 por ciento; IC95 por ciento: 35,7-66,4) y 23 al sexo masculino (48,9 por ciento; IC95 por ciento: 33,6-64,3). No hubo diferencias significativas entre la infección por Inermicapsifer madagascariensis y Taenia spp. y el sexo de los pacientes (p˃ 0,05). Conclusiones: Aunque la frecuencia de infección de las cestodiosis detectadas es baja, estos resultados pudieran ser útiles para un control integrado de las principales cestodioisis en los diferentes grupos etarios(AU)

Introduction: Cestodes are helminths of complex life cycles which may infect animals and humans. No mass deworming programs are in place to reduce the worldwide parasite load of cestodes, given the low prevalence reported by epidemiological research. Few studies are available in the international literature about the epidemiology and detection of these infections. Objective: Describe the frequency of cestode infection and its epidemiological characteristics. Methods: A retrospective descriptive study was conducted from 3 January 2010 to 28 December 2018. Evaluation was performed of all the samples of fecal matter, adult parasites and metacestodes submitted by the health care network to the Intestinal Parasitic Disease National Reference Laboratory at Pedro Kourí Institute. The study universe was 9 833 samples, mostly received from the province of Havana. Results: Inermicapsifer madagascariensis infection prevailed among children aged under 5 years (69.6 percent; CI 95 percent: 47.1-86.8). Taenia sp. intestinal infection was mainly diagnosed in patients aged 15-65 years (88.2 percent; CI 95 percent: 63.6-98.5). Of the 47 cestode infection positive cases, 24 were female (51.1 percent; CI 95 percent: 35.7-66.4) and 23 were male (48.9 percent; CI 95 percent: 33.6-64.3). No significant differences were found between Inermicapsifer madagascariensis and Taenia sp. infection and the sex of patients (p˃ 0.05). Conclusions: Although the frequency of cestode infection detected is low, these results could be useful for an integrated control of the main cestode infections affecting the different age groups(AU)

Diagnosis of intestinal protozoan infections in patients in Cuba by microscopy and molecular methods: advantages and disadvantages.

Microscopy is the gold standard for diagnosis of intestinal parasitic diseases in many countries, including Cuba, although molecular approaches often have higher sensitivity as well as other advantages. Fecal samples from 133 patients were analyzed by light microscopy and also real-time multiplex qPCR targeting Giardia duodenalis, Cryptosporidium spp., and Entamoeba histolytica, and, separately, Dientamoeba fragilis. Microscopy revealed G. duodenalis occurred most commonly (17 patients), followed by Blastocystis spp. (12 patients). In a few patients, Entamoeba histolytica/E. dispar, Cryptosporidium spp., and Cyclospora cayetanensis were identified. Molecular analysis identified 4 more G. duodenalis infections and 2 more Cryptosporidium spp. infections; concordance between microscopy and PCR showed almost perfect agreement for G. duodenalis (κ = 0.88) and substantial agreement for Cryptosporidium (κ = 0.74). PCR indicated that E. dispar, rather than E. histolytica, had been identified by microscopy. Additionally, 16 D. fragilis infections were detected using molecular methods. Although both microscopy and molecular techniques have a place in parasitology diagnostics, for parasites such as D. fragilis, where microscopy can underestimate occurrence, molecular techniques may be preferable, and also essential for distinguishing between morphologically similar microorganisms such as E. histolytica and E. dispar. Although in resource-constrained countries such as Cuba, microscopy is extremely important as a diagnostic tool for intestinal parasites, inclusion of molecular techniques could be invaluable for selected protozoa.

Prevalencia de endoparásitos en roedores sinantrópicos (Rodentia: Muridae) en una localidad de La Habana, Cuba / Prevalence of endoparasites in synanthropic rodents (Rodentia: Muridae) in an area of Havana, Cuba

Introducción: los roedores sinantrópicos se encuentran estrechamente vinculados a las condiciones de vida del hombre. Algunos de sus endoparásitos juegan un papel importante en los ciclos de muchas enfermedades parasitarias, por lo que representan un riesgo para la salud pública. Objetivo: determinar la prevalencia de grupos y especies de endoparásitos en roedores sinantrópicos en una localidad de La Habana. Métodos: el estudio se realizó en la localidad Arroyo Arenas, municipio La Lisa, provincia La Habana, Cuba. En las capturas de roedores, se emplearon trampas de captura viva. Después de realizada la eutanasia y la necropsia, se tomaron muestras fecales de la última porción del intestino grueso y del recto. Las muestras se procesaron mediante diagnóstico coproparasitológico convencional. Resultados: se capturaron un total de 78 roedores identificados como Rattus rattus, Rattus norvegicus y Mus musculus. Se registraron 13 especies de parásitos, las de mayor prevalencia fueron los nematodos Nippostrongylus brasiliensis (33,3 por ciento) y Strongyloides ratti (23,1 por ciento), y el cestodo Hymenolepis diminuta (11,5 por ciento). Conclusiones: se reportan las especies de endoparásitos en los roedores sinantrópicos. Hymenolepis diminuta es la especie de mayor prevalencia entre las especies zoonóticas, lo que demuestra su circulación activa en el ambiente. Los resultados resaltan la importancia de estos roedores como vectores potenciales de las parasitosis intestinales(AU)

Introduction: the synanthropic rodents are closely associated with human living conditions. Some of their endoparasites play an important role in many cycles of parasitic diseases, thus representing a public health risk. Objectives: to determine the prevalence of groups and species of endoparasites in synanthropic rodents in an area of Havana. Methods: the research study was carried out in Arroyo Arenas, La Lisa municipality, Havana province, Cuba. Live traps were used to capture rodents. Stool samples of the last portion of the large intestine and rectum were taken after euthanasia and necropsy. The stool samples were processed by usual parasitological diagnostic techniques. Results: a total of 78 rodents identified as Rattus rattus,Rattus norvegicus and Mus musculus were captured. Thirteen species of endoparasites were recorded, being nematodes Nippostrongylus brasiliensis (33.3 percent) and Strongyloides ratti (23.1 percent), and tapeworm Hymenolepis diminuta (11.5 percent) the most prevalent. Conclusions: some species of endoparasites are reported in the synanthropic rodents. Hymenolepis diminuta was found to be the most prevalent among zoonotic species, which shows its active circulation in the environment. This type of research highlights the importance of these rodents as potential vectors for intestinal parasitic infections(AU)

Molecular Characterization and Risk Factors of Giardia duodenalis among School Children from La Habana, Cuba.

Giardia duodenalis is considered the most common protozoan infecting humans worldwide. Molecular characterization of G. duodenalis isolates has revealed the existence of eight groups (assemblages A to H) which differ in their host distribution. A cross-sectional study was conducted in 639 children from La Habana between January and December 2013. Two assemblage-specific PCRs were carried out for the molecular characterization. The overall prevalence of Giardia infection was 11.9%. DNA from 63 of 76 (82.9%) samples was successfully amplified by PCR-tpi, while 58 from 76 (76.3%) were detected by PCRE1-HF. Similar results by both PCRs were obtained in 54 from 76 samples (71%). According to these analyses, assemblage B and mixed assemblages A + B account for most of the Giardia infections in the cohort of children tested. Our current study identified assemblage B as predominant genotype in children infected with Giardia. Univariate analysis indicated that omission of washing hands before eating and keeping dogs at home were significant risk factors for a Giardia infection. In the future, novel molecular tools for a better discrimination of assemblages at the subassemblages level are needed to verify possible correlations between Giardia genotypes and symptomatology of giardiasis.