Phylogenetic relationships of Strongyloides species in carnivore hosts.

Strongyloides stercoralis is a parasitic nematode and a major pathogen responsible for human strongyloidiasis. The presence of this species in the dog population has led to an interest in studying the phylogenetic relationships among Strongyloides spp. in carnivore hosts. In the present study, Strongyloides spp. from various carnivore hosts (raccoon, Japanese badger, Siberian weasel, raccoon dog, masked palm civet, and domestic cat) were sought. Except for civets, Strongyloides spp. were identified in all host species. Based on 18S rDNA sequences, nine OTUs (operational taxonomy units) were identified. Molecular phylogenetic analyses using 18S28S rDNA and mitochondrial cox1 (cytochrome c oxidase subunit 1) sequences clustered them into two groups. The first group (named the stercoralis/procyonis group) was comprised of six OTUs and occurred in cats, raccoon dogs, raccoons (S. procyonis), Siberian weasels, and Japanese badgers and included S. stercoralis from humans and dogs. The second group (named the planiceps group) was made up of Strongyloides spp. from raccoon dogs (two OTUs) and one OTU from Siberian weasels. Subsequent analysis using almost the full-length nucleotide sequences of protein-coding genes in their mitochondrial genomes placed Strongyloides spp. of cats in a sister taxon position to S. stercoralis, whereas S. procyonis from raccoons was more distantly related to them. The presence of Strongyloides spp. from various carnivore hosts, which are close relatives of S. stercoralis, suggests this group of Strongyloides (the stercoralis/procyonis group) essentially evolved as parasites of carnivores, although more data on Strongyloides spp. from primate hosts are needed.

Occurrence and molecular characterization of Giardia duodenalis cysts and Cryptosporidium oocysts in raw water samples from the Rímac River, Peru.

Giardia and Cryptosporidium are potentially pathogenic protozoa which are ubiquitous in ambient surface water. The present study included 60 samples of surface water from three sampling sites from the Rímac River, Lima and Callao, Peru, to detect the occurrence of Giardia spp. and Cryptosporidium spp. and to perform molecular characterization of specimens found. Water samples were concentrated using the membrane filtration technique, and following elution, cysts and oocysts were visualized by direct immunofluorescence assay (IFA). For molecular characterization, tpi and bg gene fragments and 18S rRNA were amplified by nested PCR for Giardia and Cryptosporidium, respectively, followed by sequencing and phylogenetic analysis. Giardia cysts were found in 93.3% of the analyzed samples, whereas Cryptosporidium oocysts were detected in 15%. The positivity of the Giardia cysts was 86.6% (n = 26) in 2014, while Cryptosporidium oocysts were not detected. In 2015, both protozoa were found in raw water samples, with all 30 samples collected positive for Giardia cysts (100.0%) and 9 positive for Cryptosporidium oocysts (30.0%). Oocysts were detected in 20.0% of water samples from sites 1 (mean 5.25 oocysts/L) and 2 (mean 52.3 oocysts/L), while at site 3, oocysts were detected in 50.0% of raw water samples (mean 193.6 oocysts/L). The presence of Giardia duodenalis assemblage A was confirmed in several samples by the phylogenetic positioning of the bg and tpi genes, and the sub-assemblage AII was predominant (8/9). Sequencing for Cryptosporidium resulted in profiles compatible with Cryptosporidium hominis, Cryptosporidium meleagridis, and Cryptosporidium baileyi. This is the first time that the presence of G. duodenalis assemblage A/sub-assemblage AII and Cryptosporidium species has been reported in surface water samples in Peru. These Cryptosporidium species and the Giardia duodenalis assemblage are associated with human disease which highlights the potential risk to public health and the need to increase environmental monitoring measures to protect this water body.

Estudio comparativo, prevalencia de Hymenolepis nana y otros entero parásitos en el distrito de San Lorenzo de Quinti, Huarochirí / Comparative study, prevalence of Hymenolepis nana and other enteroparasites in San Lorenzo of Quinti district, Huarochiri

Las infecciones intestinales por enteroparásitos representan un problema de salud pública en nuestro país, más aún en poblaciones rurales. Se realizó un estudio descriptivo de corte transversal sobre parasitosis intestinal en la población de 5 a 19 años (n=162) del distrito de San Lorenzo de Quinti, Huarochirí, Lima. Las muestras de heces fueron examinadas por dos métodos parasitológicos: Técnica de sedimentación Espontánea en Tubo (TSET) y la Técnica de Sedimentación Rápida (TSR), encontrándose una imprtante prevalencia de enteroparasitosis global (95.1 por ciento), siendo de éstos el 62.3 por ciento patógenos. La frecuencia de multiparasitismo fue de 84 por ciento. Predominaron protozoarios sobre helmintos. La prevalencia de protozoarios intestinales patógenos fue: Blastocystis hominis 22.8 por ciento, Giardia lamblia 22.2 por ciento, Entamoeba histolytica 4.9 por ciento. El helminto más frecuente fue Hymenolepis nana 24.1 por ciento, seguido de Fasciola hepatica 8 por ciento, Enterobius vernicularis 3.7 por ciento, Ascaris lumbricoides 2.5 por ciento, Trichuris trichiura 0.6 por ciento. La enteroparasitosis no se relacionó con el sexo (p=0.476 > 0.05). La prevalencia de H. nana disminuye con la edad en el grupo etáreo estudiado. La asociación entre cuadro clínico e infección por H. nana fue significativa para diarrea (p<0.05), no encontrándose relación en el análisis bivariado con el resto de síntomas estudiados.