Microsporidiosis and HIV:

Genotyping and zoonotic potential of Cryptosporidium and Enterocytozoon bieneusi in pigs transported across regions in China

Cryptosporidium spp. and Enterocytozoon bieneusi are common and important enteric parasites that can infect humans and animals, causing diarrhoea and systemic diseases. The objectives of the present study were to examine the prevalence and genetic variations of Cryptosporidium and E. bieneusi in pigs transferred from northeastern China to Ningbo city in Zhejiang Province. Cryptosporidium spp. was detected in 0.9% (2/216) of these samples and belonged to the zoonotic species Cryptosporidium parvum. A high E. bieneusi infection rate (25.0%, 54/216) was observed in this study, with 7 possible novel ITS genotypes (JLNB-1 to JLNB-7) and 10 known genotypes (EbpA, CM11, H, CM6, pigEBITS1, EbpC, CS-4, pigEBITS5, CHS5, and Henan-Ⅳ) identified, and zoonotic EbpA was the dominant genotype. Genotypes H and pigEBITS1 were reported for the first time in pigs in China. Phylogenetic analysis indicated that all the genotypes found in these samples belonged to zoonotic group 1. These findings indicated the potential threat of Cryptosporidium and E. bieneusi to humans or the environment during cross-regional transportation. An effective management control system should be built to avoid parasitic transmission as well as other animal diseases while travelling across different regions. In further studies, attention should be given to the transmission routes and the role of pigs as a potential source of human Cryptosporidium and E. bieneusi infections in China.

Molecular detection of porcine Enterocytozoon bieneusi infection in Peninsular Malaysia and epidemiological risk factors associated with potentially zoonotic genotypes

Enterocytozoon bieneusi is an emerging opportunistic pathogen infecting humans, and both domestic and wild pigs are known to harbour zoonotic genotypes. There remains a paucity of information on the prevalence and epidemiology of this enteropathogen in Southeast Asia. The present study was undertaken to determine the molecular prevalence and risk factors associated with E. bieneusi infection among commercially farmed pigs in Malaysia. Faecal samples were collected from 450 pigs from 15 different farms and subjected to nested PCR amplification of the ribosomal internal transcribed spacer (ITS) gene of E. bieneusi. Phylogenetic analysis involved 28 nucleotide sequences of the ITS region of E. bieneusi. An interviewer-administered questionnaire provided information on the animal hosts, farm management systems and environmental factors and was statistically analysed to determine the risk factors for infection. The prevalence of E. bieneusi infection was relatively high (40.7%). The highest prevalence (51.3%) was recorded among the piglets, while the adults showed the lowest level of infection (31.3%). Multivariate analysis indicated that age of the pigs, distance of the farm from human settlement and farm management system were significant risk factors of infection. Three genotypes (EbpA, EbpC and Henan-III) detected among the pigs are potentially zoonotic. The high prevalence of E. bieneusi among locally reared pigs, the presence of zoonotic genotypes and the spatial distribution of pig farms and human settlements warrant further investigation on the possibility of zoonotic transmission.

Screening of opportunistic Encephalitozoon intestinalis and Enterocytozoon bieneusi in immunocompromised patients in Slovakia

OBJECTIVE

In recent years new infectious diseases, i.e. emerging or re-emerging diseases, have been coming to the forefront. Currently, microsporidia, considered to be a major cause of emerging and opportunistic infections particularly in immunocompromised individuals, are also included in this group. Therefore, the aim of our study was to map the prevalence of Encephalitozoon intestinalis and Enterocytozoon bieneusi infection in a group of patients and to compare it with the occurrence of specific antigens in immunocompetent people.

METHODS

Detection of spores of both pathogens in faecal samples was performed by an immunofluorescence test using species-specific monoclonal antibodies.

RESULTS

Positivity to E. intestinalis in 91 examined immunosuppressed patients reached 33% (30/91), while only 4.3% (3/70) of the control group samples were found to be positive (relative risk 7.7, p < 0.001). In case of E. bieneusi 14.3% (13/91) of immunocompromised patients were positive, as were 5.7% (4/70) of people from the control group (relative risk 2.5, p = 0.095).

CONCLUSION

In case of development of any opportunistic infection, the infection is detected and removed in most cases at an early stage. The incidence of clinically manifested microsporidiosis in patients with immunodeficiency is rare as they are under constant medical supervision. However, we must not forget about opportunistic infections, and in case of any non-specific symptoms it is necessary to exclude or confirm the diagnosis for immediate treatment.

Infection by and genotype characteristics of Enterocytozoon bieneusi in HIV/AIDS patients from Guangxi Zhuang autonomous region, China

Background

Enterocytozoon bieneusi has been increasingly reported to infect humans and various mammals. Microsporidia cause diarrhea in HIV-infected patients worldwide. PCR amplification and sequencing based on the internal transcribed spacer region have been used to describe the genotypes of E. bieneusi and transmission of microsporidiosis.

Methods

In this study, we examined E. bieneusi infection and genotypes in HIV-positive patients in Guangxi, China. Stool specimens were collected from 285 HIV-positive patients and 303 HIV-negative individuals. E. bieneusi genotypes were characterized using nested PCR and sequencing.

Results

Thirty-three (11.58%) HIV-positive patients were infected with microsporidia, and no infection was found in the 303 healthy controls. Three new genotypes were identified and named as GX25, GX456, and GX458; four known genotypes, PigEBITS7, Type IV/K, D, and Ebpc, were also identified. Our data showed that the positive rate for microsporidia was significantly higher in the rural patients than in the other occupation groups. In addition, the positive rate for microsporidia was significantly higher in the patients who drink unboiled water than in those with other drinking water sources.

Conclusions

Our results will provide baseline data for preventing and controlling E. bieneusi infection in HIV/AIDS patients. Further studies are required to clarify the epidemiology and potential sources of microsporidia. Our study showed that microsporidium infection occurs in the HIV/AIDS patients in Guangxi, China.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2787-9) contains supplementary material, which is available to authorized users.

Therapeutic strategies for human microsporidia infections

Over the past 20 years, microsporidia have emerged as a cause of infectious diseases in AIDS patients, organ transplant recipients, children, travelers, contact lens wearers and the elderly. Enterocytozoon bieneusi and the Encephalitozoon spp., Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis, are the most frequently identified microsporidia in humans, and are associated with diarrhea and systemic disease. The microsporidia are small, single-celled, obligately intracellular parasites that have been identified in water sources, as well as in wild, domestic and food-producing farm animals, thereby raising concerns for waterborne, foodborne and zoonotic transmission. Current therapies for microsporidiosis include albendazole, a benzimidazole that inhibits microtubule assembly and is effective against several microsporidia, including the Encephalitozoon spp., although it is less effective against Encephalitozoon bieneusi. Fumagillin, an antibiotic and antiangiogenic compound produced by Aspergillus fumigatus, is more broadly effective against Encephalitozoon spp. and E. bieneusi; however, is toxic when administered systemically to mammals. Recent studies are also focusing on compounds that target the microsporidia polyamines (e.g., polyamine analogs), methionine aminopeptidase 2 (e.g., fumagillin-related compounds), chitin inhibitors (e.g., nikkomycins), topoisomerases (e.g., fluoroquinolones) and tubulin (e.g., benzimidazole-related compounds).

Epidemiology of microsporidiosis: sources and modes of transmission

Microsporidia are single-celled, obligate intracellular parasites that were recently reclassified from protozoa to fungi. Microsporidia are considered a cause of emerging and opportunistic infections in humans, and species infecting humans also infect a wide range of animals, raising the concern for zoonotic transmission. Persistent or self-limiting diarrhea are the most common symptoms associated with microsporidiosis in immune-deficient or immune-competent individuals, respectively. Microsporidian spores appear to be relatively resistant under environmental conditions, and species of microsporidia infecting humans and animals have been identified in water sources, raising concern about water-borne transmission. Sensitive and specific immunomagnetic bead separation and PCR-based methods are being developed and applied for detecting microsporidia in infected hosts and water sources for generating more reliable prevalence data. The most effective drugs for treating microsporidiosis in humans currently include albendazole, which is effective against the Encephalitozoon species but not against Enterocytozoon bieneusi, and fumagillin, which has broader anti-microsporidia activity but is toxic in mammals, suggesting a need to identify better drugs. Strategies to capture and disinfect microsporidia in water are being developed and include filtration, coagulation, chlorination, gamma-irradiation, and ozonation.