Pathogens causing diarrhoea among Bangladeshi children with malignancy: Results from two pilot studies

Potential Zoonotic Transmission of Giardia duodenalis between Children and Calves in Bangladesh

Giardia duodenalis is a zoonotic protozoan parasite that causes gastrointestinal illness in humans and livestock. We studied the genetic diversity of G. duodenalis in children and calves from Bangladesh to determine its zoonotic potential. Fecal samples collected from children (299) and calves (699) were screened with nested PCR with primers targeting the ssu rRNA gene for G. duodenalis. Positive samples were further multilocus genotyped using the β-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes. The overall infection rate of G. duodenalis was 21.1% (63/299) in children and 5.7% (40/699) in calves. There were no significant differences in infection with G. duodenalis among age groups, sex, and study areas in children and calves. Multilocus genotyping (MLG) of human G. duodenalis identified zoonotic assemblages A (34.0%, 18/53) and B (50.9%, 27/53) and a so-called ruminant-specific assemblage E (11.3%, 6/53), as well as two mixed assemblages, B/D (1/53) and B/E (1/53). Assemblage E predominated in calves (82.3%, 28/34), followed by assemblages A (11.8%, 4/34) and B (5.9%, 2/34). Overall, zoonotic assemblages A, B, and E were found in 6.0% (18/299), 9.0% (27/299), and 2.0% (6/299) of the children’s stool samples, respectively, and 0.6% (4/699), 0.3% (2/699), and 4.0% (28/699) of the calf fecal samples, respectively. Although there was a difference in the distribution of subassemblages in humans (mostly AII) and calves (mostly AI), the zoonotic assemblages A, B, and E present in both children and calves suggest the potential for zoonotic transmission of G. duodenalis. This molecular study highlights the fact that G. duodenalis infections were common in the study areas, with potential zoonotic transmission between children and calves, implying that cattle might play a role in G. duodenalis zoonotic transmission.

Molecular prevalence of Cryptosporidium isolates among Egyptian children with cancer

Immunocompromised individuals especially children with cancer are at risk for acquiring cryptosporidiosis, which can result in severe morbidity and mortality. This work was conducted to evaluate the prevalence of Cryptosporidium parasite and its genotypes in children with cancer. Stool specimens were collected from 145 children in the Oncology unit of Pediatric Department, Zagazig University Hospital, Sharqiyah province, Egypt. Cryptosporidium infection was evaluated using modified Ziehl-Neelsen (MZN) staining and nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The prevalence of Cryptosporidium infection in oncological children was 29.7% using microscopy and 25.5% using nested PCR. Genotypic characterization showed that 23 (62.2%) had C. hominis, 11 (29.7%) C. parvum, and 3 specimens (8.1%) were mixed infection of both genotypes. Cryptosporidiosis was significantly associated with diarrhea. However, no statistically significant difference was detected between the age, gender, residency, animal contact and malignancy type concerning to Cryptosporidium infection. This study concluded that Cryptosporidium is a prevailing opportunistic parasite among children with cancer. It should be considered in oncological patients especially those suffering from diarrhea which requires proper management to reduce its complications.