Risk Factors and Spatial Clusters of Cryptosporidium Infection among School-Age Children in a Rural Region of Eastern China

Prevalence of Cryptosporidium infection in children from China: a systematic review and meta-analysis

Cryptosporidium is an important zoonotic pathogen that causes diarrhea in humans and animals, and a leading cause of diarrhea morbidity and mortality in children under 5 years old. However, the meta-analysis of Cryptosporidium infection in children in China has not been published. We searched the databases for articles published on the prevalence of Cryptosporidium infection in children in China since the inception of these databases to 31 October 2022. The prevalence of Cryptosporidium infection in children was estimated using a random effects model. The results showed that 111 datasets from 24 provinces were selected for the final quantitative analysis. The estimated pooled Cryptosporidium infection prevalence in children in China was 2.9% (3300/126,381). The highest prevalence rate was in southwestern China (4.8%, 365/7766). Subgroup analysis indicated that the Cryptosporidium infection rate in children aged < 3 years (4.9%, 330/8428) was significantly higher than that in children aged 3-6 years (2.5%, 609/26,080) and >6 years (2.6%, 647/27,586). Six Cryptosporidium species were detected in children in China from the selected studies. C. hominis was the dominant species (77.1%, 145/188) and the proportions of subgenotype IaA14R4 of C. hominis was highest (42.8%, 62/145). The findings suggest that Chinese children is in a low level of Cryptosporidium infection, however, the geographical distribution of the infection is extensive. We suggest that measures should be taken to ensure the healthy growth of Chinese children by improving the water environment, increasing public health facilities, strengthening children's health education, and developing sound Cryptosporidium infection control programs.

Prevalence of cryptosporidiosis among children with diarrhoea under five years admitted to Kosti teaching hospital, Kosti City, Sudan

Background

Cryptosporidiosis is a disease caused by infection with an intestinal coccidian parasite Cryptosporidium. Cryptosporidium species are the second leading cause of diarrheal disease and death in children in developing countries. Until now, no data have been available or published on its prevalence among children with diarrhea in Sudan. Therefore, this paper was designed to determine the prevalence rate of Cryptosporidium among children with diarrhea under 5 years who were admitted to Kosti Teaching Hospital.

Methods

A hospital-based cross-sectional study including children under 5 years old admitted to the pediatric section of the hospital between September 2020 and December 2020. A total of one-hundred and fifty stool samples were collected. All stool samples were examined using the modified Ziehl Neelsen (mZN) staining technique and then examined microscopically for Cryptosporidium infection.

Results

A total of 150 children were examined out of which 70 presented with diarrhea. A greater prevalence of 19/70 (27.1%) of Cryptosporidium was observed in children with diarrhea than children without diarrhea 7/80 (8.8%). There was a significant relationship between the prevalence of Cryptosporidium and the presence of diarrhea in children under 5 years in the Kosti Teaching Hospital(P < 0.05). It was found that a higher prevalence was registered among children using piped-water sources for drinking.

Conclusions

The overall prevalence of parasite detected was 17.3% among children admitted to Kosti Teaching Hospital. The prevalence rate of the infection among Children with diarrhoea was 27.1%. Studying the prevalence rate of cryptosporidiosis among diarrheic children may predict their health status, leading to a better diagnosis, treatment, and, therefore, patients’ status improvement.

Molecular Epidemiology of Human Cryptosporidiosis in Low- and Middle-Income Countries

Cryptosporidiosis is one of the most important causes of moderate to severe diarrhea and diarrhea-related mortality in children under 2 years of age in low- and middle-income countries. In recent decades, genotyping and subtyping tools have been used in epidemiological studies of human cryptosporidiosis. Results of these studies suggest that higher genetic diversity of Cryptosporidium spp. is present in humans in these countries at both species and subtype levels and that anthroponotic transmission plays a major role in human cryptosporidiosis. Cryptosporidium hominis is the most common Cryptosporidium species in humans in almost all the low- and middle-income countries examined, with five subtype families (namely, Ia, Ib, Id, Ie, and If) being commonly found in most regions. In addition, most Cryptosporidium parvum infections in these areas are caused by the anthroponotic IIc subtype family rather than the zoonotic IIa subtype family. There is geographic segregation in Cryptosporidium hominis subtypes, as revealed by multilocus subtyping. Concurrent and sequential infections with different Cryptosporidium species and subtypes are common, as immunity against reinfection and cross protection against different Cryptosporidium species are partial. Differences in clinical presentations have been observed among Cryptosporidium species and C. hominis subtypes. These observations suggest that WASH (water, sanitation, and hygiene)-based interventions should be implemented to prevent and control human cryptosporidiosis in low- and middle-income countries.

Performance of formalin ethyl acetate, percoll sedimentation and ELISA for the detection of Cryptosporidium infection in asymptomatic children

This study aimed to assess the performance of formalin ethyl acetate (FEA)/modified Ziehl-Neelsen (MZN), and percoll technique/MZN for the diagnosis of cryptosporidiosis among asymptomatic children compared to ELISA coproantigen. The study was conducted on 100 children in a rural area in Kafr El-Sheikh governorate. Stool samples were collected and examined by the three techniques. Microscopic examination revealed the presence of acid-fast stained oocysts and non-acid fast ghost oocysts. The overall prevalence rate was 7% with an infection intensity of 1-5 oocysts/oil immersion field. FEA/MZN technique showed the highest diagnostic performance (5%) with 71.4% sensitivity and 98% negative predictive value (NPV) compared to the other techniques. ELISA revealed 3% prevalence, 42.9% sensitivity and 96% NPV. Percoll/MZN gave the lowest prevalence, sensitivity and NPV (1%, 14.29% and 93.9% respectively). Agreement fluctuated between moderate and poor regarding FEA/MZN versus ELISA and percoll/MZN versus both techniques. In conclusion, FEA/MZN gave the top diagnostic performance, yet it missed some positive cases. Its combination with ELISA coproantigen might prove beneficial for Cryptosporidium diagnosis. Percoll technique needs more validation by modifying the density gradient, speed of centrifugation, and staining methods.

First report of Cryptosporidium viatorum and Cryptosporidium occultus in humans in China, and of the unique novel C. viatorum subtype XVaA3h

BACKGROUND

Cryptosporidium is a genus of common intestinal protozoa, members of which cause diarrhea in a wide variety of hosts. Previous studies on Cryptosporidium in China have mainly focused on diarrhea sufferers, children, and immunodeficient individuals such as HIV/AIDS patients. However, the epidemiological characteristics of Cryptosporidium in the population in rural areas remain unclear. Herein, we investigated the prevalence of, and risk factors for, Cryptosporidium in rural areas of Binyang County, Guangxi Zhuang Autonomous Region, China, and genetically characterized the Cryptosporidium isolates we obtained.

METHODS

From August to December 2016, two villages in Binyang County, Guangxi, were sampled using a random cluster sampling method. Fresh fecal samples were collected from all eligible residents (residence time > 6 months). Molecular characterization of Cryptosporidium was carried out based on its SSU rRNA, gp60, actin and hsp70 gene sequences. Fisher's exact test were conducted to assess the risk factors for Cryptosporidium infection.

RESULTS

A total of 400 fecal samples were collected from 195 males (48.8%) and 205 females (51.2%). Two samples (0.5%) were positive for Cryptosporidium and were identified as C. viatorum and C. occultus respectively. Moreover, a new C. viatorum subtype XVaA3h was identified based on the sequence of the gp 60 gene.

CONCLUSIONS

To our knowledge, this is the first report of C. viatorum and C. occultus infections in humans in China and of C. viatorum subtype XVaA3h. The findings provide important information on the prevalence of Cryptosporidium in the Chinese population, and expand the range of Cryptosporidium species known to infect people in China.

Molecular characterization of three intestinal protozoans in hospitalized children with different disease backgrounds in Zhengzhou, central China

Background

Cryptosporidium spp. and Giardia duodenalis are major intestinal pathogens that can cause diarrheal diseases in humans, especially children. Enterocytozoon bieneusi is another parasite which can cause gastrointestinal tract disorders, with diarrhea being the main clinical symptom. However, few genetic studies of these parasites in pediatric inpatients in China have been published.

Methods

To assess the genetic characteristics and epidemiological status of these parasites, a total of 2284 fecal samples were collected from children in the pediatric departments of three hospitals in Zhengzhou, central China, and screened for these protozoans with PCR, based on the small subunit ribosomal RNA (SSU rRNA) genes of Cryptosporidium spp. and G. duodenalis and the internal transcribed spacer (ITS) of E. bieneusi.

Results

Six (0.26%), 14 (0.61%), and 27 (1.18%) of the samples were positive for Cryptosporidium spp., G. duodenalis and E. bieneusi, respectively. Of the 12 successfully sequenced G. duodenalis isolates, four were identified as assemblage A and eight as assemblage B. In subtype and multilocus genotype (MLG) analyses, C. parvum IIdA19G1 (n = 4) and two novel G. duodenalis MLGs belonging to subassemblage AII (n = 3) and BIV (n = 5) were successfully identified. The E. bieneusi isolates included genotypes D (n = 17), J (n = 2), PigEBITS7 (n = 1), BEB6 (n = 1), and CM8 (n = 1). This is the first report of C. parvum subtype IIdA19G1 in HIV-negative children and E. bieneusi genotype CM8 in humans.

Conclusions

The dominance of zoonotic C. parvum subtype IIdA19G1 indicates that this parasite is turning into zoonotic origin from human-to-human transmission. The phylogenetic analysis also revealed the zoonotic origins and anthroponotic transmission potential of G. duodenalis and E. bieneusi, suggesting more efforts must be made to minimize the threat these pathogens pose to public health.

Intestinal parasitic infection among household contacts of primary cases, a comparative cross-sectional study

Background

Intestinal parasitic infection affects 3.5 billion people in the world and mostly affecting the low socio-economic groups. The objectives of this research works were to estimate the prevalence and determinants of intestinal parasitic infection among family members of known intestinal parasite infected patients.

Methods and materials

A comparative cross-sectional study design was implemented in the urban and rural settings of Mecha district. The data were collected from August 2017toMarch 2019 from intestinal parasite infected patient household members. Epi-info software was used to calculate the sample size, 4531 household members were estimated to be included. Data were collected using interview technique, and collecting stool samples from each household contact of intestinal parasite patients. Descriptive statistics were used to estimate the prevalence of intestinal parasites among known contacts of intestinal parasite patients/family members. Binary logistic regression was used to identify the determinant factors of intestinal parasitic infection among family members.

Results

The prevalence of intestinal parasite among household contacts of intestinal parasite-infected family members was 86.14% [95% CI: 86.14% - 87.15%]. Hookworm infection was the predominant type of infection (18.8%). Intestinal parasitic infection was associated with sex, environmental sanitation, overcrowding, personal hygiene, residence, substandard house, role in the household, source of light for the house, trimmed fingernails, family size, regular handwashing practice. Protozoa infection was associated with habit of ingesting raw vegetable, playing with domestic animals, water source and the presence of household water filtering materials.

Conclusion

High prevalence of intestinal parasitic infection was observed among household contacts of primary cases.