Cryptosporidium and cryptosporidiosis in wild birds: A One Health perspective

Identifying zoonotic risks: molecular insights into Cryptosporidium and Enterocytozoon bieneusi in pediatric cancer patients in Ahvaz, 2024

Opportunistic infections remain a major cause of morbidity and mortality among patients with immunodeficiency and malignancy. Cryptosporidium spp. and microsporidia, particularly Enterocytozoon bieneusi, are obligate intracellular parasites that can lead to severe complications and even death in immunocompromised individuals.In this cross-sectional study, 60 stool samples were collected from pediatric oncology patients aged 5-18 years who were hospitalized at Baghaei 2 Hospital in Ahvaz, southwestern Iran, in 2024. Following DNA extraction, molecular analysis was performed to detect the presence of Cryptosporidium spp. and E. bieneusi. For genotyping, amplification and sequencing of the 60-kDa glycoprotein (gp60) gene for Cryptosporidium spp. and the internal transcribed spacer (ITS) region for E. bieneusi were conducted. A total of 16 samples (26.6%) tested positive for either C. hominis or E. bieneusi. Co-infection with both pathogens was identified in two patients (3%). Statistical analysis revealed no significant association between gender and parasitic infection (P = 0.166), nor between the type of malignancy and presence of protozoa (P = 0.717). Genotyping of E. bieneusi showed the presence of BEB6, CHG3, D, and I genotypes, with BEB6 being the most prevalent. Subtyping of C. hominis revealed the presence of the IeA11G3T3 subtype. Overall, the molecular findings demonstrated a prevalence rate 26.6 % of parasitic infection among the studied population, with E. bieneusi being predominant. The detection of potentially zoonotic genotypes, particularly BEB6, underscores the likelihood of zoonotic transmission routes in these patients.

Cryptosporidium Spp. in Mink, Foxes, and Raccoon Dogs in Five Provinces of Northern China

Cryptosporidium spp. is a common intestinal pathogen that causes diarrhea in both humans and animals. Northern China has a large-scale fur animal farming industry. Although there have been related studies, systematic data remain lacking. In this study, a total of 871 fecal samples were collected from fur animals in Shandong, Hebei, Liaoning, Jilin, and Heilongjiang provinces. Using nested polymerase chain reaction, 75 Cryptosporidium-positive samples were detected, and the overall infection rate was 8.61%. The infection rates ranged from 4.23% to 16.81% across different provinces, with the highest rate was observed in Shandong (16.81%, 19/113), followed by Jilin (15.07%, 11/73). Additionally, foxes (15.06%, 53/352) showed a higher infection rate compared with mink (4.55%, 13/286) and raccoon dogs (3.86%, 9/233), suggesting that foxes may be more susceptible. Four species/genotypes were identified: Cryptosporidium canis (n = 66), Cryptosporidium meleagridis (n = 1), Cryptosporidium parvum (n = 1), and mink genotype (n = 7). Among these, C. parvum and C. meleagridis were found in raccoon dogs and foxes, respectively, while the mink genotype was detected only in mink. C. canis was present in all three animal species and was the dominant species in foxes. These findings indicate that farmed fur animals may serve as potential reservoirs for Cryptosporidium transmission to humans. This study provides essential epidemiological data on Cryptosporidium infections in fur animals, contributing to a better understanding of its distribution and potential zoonotic risk.

Respiratory and intestinal zoonotic cryptosporidiosis in symptomatic domestic pigeons (Columba livia domestica) in Tabriz, Iran

Background

Domestic pigeons (Columba livia domestica) are the oldest domesticated birds worldwide, harboring many zoonotic parasites and posing potential public health threats.

Aims

To investigate cryptosporidiosis in domestic pigeons in Tabriz, Iran, 100 privately owned pigeons presenting weight loss and diarrhea were tested for Cryptosporidium spp. through parasitological, histopathological, and molecular tests.

Methods

Modified Ziehl-Neelsen-stained fecal smears and histological sections of the trachea and small intestine were examined microscopically. Genomic DNA of fecal and tracheal specimens was examined by nested conventional PCR targeting 18S rDNA, followed by Sanger sequencing of histopathology-confirmed samples and phylogenetic analyses.

Results

All pigeons were positive at PCR in their feces and trachea. Oocysts similar to the size of Cryptosporidium species were observed in stained fecal smears of 62% of pigeons. At the histopathological examination, Cryptosporidium-organisms were observed on the apical epithelial surfaces of the small intestine in 84% and trachea in 78% of pigeons. In 23 pigeons, simultaneous tracheal and intestinal cryptosporidiosis was determined. The lesions in affected tracheas and small intestines included hyperemia, villous atrophy and fusion, dilatation of intestinal crypts, irregular epithelial hyperplasia, and sloughing. Diffused mixed inflammatory cell infiltration in the lamina propria was observed, with dominant lymphocytes, plasma cells, and lower numbers of heterophils. Consensus sequences of detected parasites revealed infection with Cryptosporidium parvum and Cryptosporidium meleagridis.

Conclusion

Considering the high frequency of cryptosporidiosis reported here in symptomatic birds and that both identified Cryptosporidium species are zoonotic parasites, findings claim a public health risk assessment of this species of animals.

Molecular Detection and Characterization of Cryptosporidium spp. and Giardia duodenalis in Dairy Calves from Ningxia, China

PURPOSE

Cryptosporidium spp. and Giardia duodenalis are two important foodborne human and animal parasites that can be disseminated through both food and water, leading to diarrheal disease. Nevertheless, available information on the circumstances of Cryptosporidium and Giardia duodenalis from Ningxia is limited.

METHODS

A total of 208 stool samples of dairy calves derived from large-scale farms (> 1000 heads) of five cities randomly in Ningxia were gathered randomly, were amplified and analyzed by nested PCR based on the three target genes (18S rRNA, gp60 and tpi)and phylogenetic systematics.

RESULTS

The prevalence of cryptosporidiosis and giardiasis in dairy calves in Ningxia were 13.0% (27/208 samples, 95% CI 9.1-18.2%) and 1.9% (4/208, 95% CI 0.8-4.9%) respectively. Three Cryptosporidium species appeared in this study which are Cryptosporidium parvum (C. parvum), Cryptosporidium andersoni (C. andersoni) and Cryptosporidium ryanae (C. ryanae) based on the 18S rRNA gene sequence. IIdA15G1 and IIdA13G1 belonging to the subtypes of Cryptosporidium were detected by the gp60 PCR. The genotypes of Giardia duodenalis were only assemblage E through the amplification of the triosephosphate-isomerase gene (tpi gene).

CONCLUSION

There is a risk of transmission to humans in Ningxia because of zoonotic genotypes (C. parvum, C. andersoni, assemblage E) and subtypes (IId) of Cryptosporidium spp. and G. duodenalis in dairy calves, and it is necessary to pay attention to the disease to prevent a widespread epidemic of the disease with the purpose to protect human and livestock health.

Molecular Screening and Characterization of Enteric Protozoan Parasites and Microsporidia in Wild Ducks from Portugal

Enteric parasites pose significant threats to both human and veterinary health, ranking among the top causes of mortality worldwide. Wild migratory waterfowl, such as ducks, may serve as hosts and vectors for these parasites, facilitating their transmission across ecosystems. This study conducted a molecular screening of enteric parasites in three species of wild ducks of the genus Anas (A. acuta, A. platyrhynchos and A. crecca) from Portugal, targeting Blastocystis sp., Balantioides coli, Cryptosporidium spp., Encephalitozoon spp., and Enterocytozoon bieneusi. Fecal samples from 71 ducks were analyzed using PCR and sequencing techniques. The results revealed a 2.82% occurrence of Blastocystis sp. subtype 7 and Cryptosporidium baileyi, marking the first molecular detection of these pathogens in wild ducks in Portugal. While previous studies have documented these parasites in Anas spp. in other regions, this study contributes novel data specific to the Portuguese context. No evidence of Balantioides coli, Encephalitozoon spp. or Enterocytozoon bieneusi was found. These findings highlight the potential role of migratory ducks as vectors for zoonotic protozoa, emphasizing the need for enhanced surveillance of avian populations to mitigate cross-species transmission risks. Further research is warranted to understand the global public health implications associated with migratory waterfowl.

Genetic characterizations of Cryptosporidium spp. from children with or without diarrhea in Wenzhou, China: high probability of zoonotic transmission

BACKGROUND

Cryptosporidium is a highly pathogenic parasite responsible for diarrhea in children worldwide. Here, the epidemiological status and genetic characteristics of Cryptosporidium in children with or without diarrhea were investigated with tracking of potential sources in Wenzhou City, China.

METHODS

A total of 1032 children were recruited, 684 of whom had diarrhea and 348 without, from Yuying Children's Hospital in Wenzhou, China. Samples of stool were collected from each participant, followed by extraction of DNA, genotyping, and molecular identification of Cryptosporidium species and subtypes.

RESULTS

Twenty-two of the 1032 (2.1%) children were infected with Cryptosporidium spp. with 2.5% (17/684) and 1.4% (5/348) in diarrhoeic and asymptomatic children, respectively. Four Cryptosporidium species were identified, including C. parvum (68.2%; 15/22), C. felis (13.6%; 3/22), C. viatorum (9.1%; 2/22), and C. baileyi (9.1%; 2/22). Two C. parvum subtypes named IIdA19G1 (n = 14) and IInA10 (n = 1), and one each of C. felis (XIXa) and C. viatorum (XVaA3g) subtype was found as well.

CONCLUSIONS

This is the first research that identified Cryptosporidium in children of Wenzhou, China, using PCR. Identification of zoonotic C. parvum, C. felis, C. viatorum, and their subtypes indicate potential cross-species transmission of Cryptosporidium between children and animals. Additionally, the presence of C. baileyi in children suggests that this species has a wider host range than previously believed and that it possesses the capacity to infect humans.

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China

BACKGROUND

Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers.

METHODS

A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products.

RESULTS

By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116).

CONCLUSIONS

The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

The risk of wild birds contaminating source water with zoonotic Cryptosporidium and Giardia is probably overestimated

Cryptosporidium and Giardia are important waterborne protozoan parasites that are resistant to disinfectants commonly used for drinking water. Wild birds, especially wild migratory birds, are often implicated in the contamination of source and wastewater with zoonotic diseases, due to their abundance near water and in urban areas and their ability to spread enteric pathogens over long distances. This review summarises the diversity of Cryptosporidium and Giardia in birds, with a focus on zoonotic species, particularly in wild and migratory birds, which is critical for understanding zoonotic risks. The analysis revealed that both avian-adapted and zoonotic Cryptosporidium species have been identified in birds but that avian-adapted Cryptosporidium species dominate in wild migratory birds. Few studies have examined Giardia species and assemblages in birds, but the non-zoonotic Giardia psittaci and Giardia ardeae are the most commonly reported species. The identification of zoonotic Cryptosporidium and Giardia in birds, particularly C. parvum and G. duodenalis assemblages A and B in wild migratory birds, is likely due to mechanical carriage or spillback from birds co-grazing pastures contaminated with C. parvum from livestock. Therefore, the role of wild migratory birds in the transmission of zoonotic Cryptosporidium and Giardia to source water is likely overestimated. To address knowledge gaps, it is important to conduct more extensive studies on the prevalence of Cryptosporidium and Giardia in a broader range of migratory wild birds. There is also a need to investigate the extent to which zoonotic infections with C. hominis/C. parvum and G. duodenalis assemblages A and B are mechanical and/or transient, and to assess the load and viability of zoonotic oo/cysts shed in avian faeces. Understanding the contribution of birds to zoonoses is essential for effective disease surveillance, prevention, and control.

Study on genetic characteristics of Cryptosporidium isolates and first report of C. parvum IIdA24G2 subtype in dairy cattle in China

Cryptosporidium is an important gastrointestinal parasite that can cause mild to severe diarrhea in various vertebrates, including humans and domestic animals. Infection is prevalent in dairy cattle, particularly calves, resulting in diarrhea and increased mortality with significant production losses. However, the prevalence and identity of Cryptosporidium spp. in cattle in Heilongjiang Province is still poorly known. Our study aimed to investigate the prevalence and species and subtype distribution of Cryptosporidium in cattle in the region. In addition, we evaluated the zoonotic potential of Cryptosporidium isolates and assessed possible transmission routes and health effects of this organism. We collected 909 fecal samples from five different farms in Heilongjiang Province between August and September 2022. The samples underwent Cryptosporidium detection by nested PCR and small subunit (SSU) rRNA gene sequence analysis. Four Cryptosporidium species were identified, including C. parvum, C. bovis, C. ryanae, and C. andersoni, with an overall prevalence of 4.4% (40/909). Based on sequence analysis of the 60 kDa glycoprotein gene of C. parvum and C. bovis, three subtypes of C. parvum were identified, namely two previously known subtypes (IIdA19G1 and IIdA20G1), and one novel subtype (IIdA24G2). Two distinct subtype families were identified in C. bovis (XXVId and XXVIe). The high diversity of Cryptosporidium in dairy cattle and the emergence of a novel subtype of C. parvum in Heilongjiang Province suggest that dairy cattle may serve as a significant source of zoonotic cryptosporidiosis infection in this region.

Dominant infection of Cryptosporidium baileyi in broiler chickens in Zhejiang Province, China

Cryptosporidium is a common enteric parasite in chickens. A total of 812 fecal specimens were collected from 11 broiler farms in Zhejiang Province, China, and analyzed by nested PCR amplification based on the small subunit ribosomal RNA (SSU rRNA) gene. The overall infection rate of Cryptosporidium was 6.3% (51/812), and five of 11 farms were Cryptosporidium positive. Broilers aged > 90 days accounted for the highest infection rate of 16.1% (6/56), followed by those aged 30-60 days (10.6%, 38/358) and 60-90 days (4/378, 1.1%). Two Cryptosporidium species were identified by sequence analysis, with the predominant species being C. baileyi (96.1%, 49/51) and the minor infection being C. meleagridis (3.9%, 2/51). Based on the 60-kDa glycoprotein (gp60) gene, two C. meleagridis-positive isolates were identified as one known subtype, IIIbA24G1R1. This study indicated the common occurrence of C. baileyi in broiler chickens in this region and low zoonotic transmission potential of Cryptosporidium to humans.

Dual mechanism (sunlight/dark) of the self-assembly nitazoxanide drug on cellulose nanocrystal surface for destroying the Cryptosporidium parvum oocysts

Destruction of the cryptosporidium parvum (C. parvum) Oocysts is the main target of the work via the improvement effect of the nitazoxanide (NTZ) drug by increasing the drug adsorption process without changing the cell viability. The synthesis of a self-assembly nanocomposite (NCP) of cellulose nanocrystals (CNC) and NTZ drug was performed successfully via the chemical precipitation methods without utilizing the temperature. Also, the characterization of the fabricated NCP was achieved by different techniques to confirm the natural formation of the NCP. The efficient loading of the NTZ drug on the CMC surface and the release process of NCP was calculated by a UV-Visible spectroscopy device, and the loading efficiency is 37 %. The release efficiency is displayed at 66.3 % after 6 h, and 97 % after 48 h at pH 7.4 with NTZ pure, while the release efficiency of CNC@NTZ at the same pH is 61 % after 6 h, and 86 % after 48 h at pH 7.4. The cytotoxicity of different concentrations of NCP was conducted on normal mouse liver cells (BNL) via the quick screening cytotoxicity method (SRB). The effect of NCP on C. parvum was detected with an in-vivo study in the dark and under sunlight conditions. Compared to the NTZ and CNC, the fabricated NCP was able to destroy 89.3 % of the oocyst wall after 96 h. Moreover, a sporulation inhibition percentage of 53.97 % ± 0.63 % was achieved by a maximum concentration of 7 mg/mL after 9.5 h. The results are very encouraging to use the modified NCP as an alternative NTZ drug, although further research is required in terms of clinical trials.

Migrating Anatidae as Sources of Environmental Contamination with Zoonotic Giardia, Cryptosporidium, Cyclospora and Microsporidia

Giardia, Cryptosporidium, Cyclospora, and microsporidia are gastrointestinal pathogens that can cause various disease symptoms in both animals and humans. Numerous studies worldwide have confirmed the presence of these eukaryotic pathogens in nesting and migrating wild geese, ducks, and swans. Migration spreads these zoonotic enteric pathogens to distant locations, which could have public health implications. Soils and water bodies (lakes, ponds, rivers and wetlands) in urban and suburban areas have been shown to be vulnerable to contamination by waterfowl droppings. This review addresses the epidemiology of these enteric pathogens in wild migratory bird species (Anatidae) and some consequences of their spread in the environment. To date, both zoonotic pathogens and genotypes restricted to avian hosts have been found in faecal samples from 21 anatid species worldwide. One of the routes of infection for these zoonotic gastrointestinal micropathogens is the indirect route. For example, shared water bodies (e.g., for drinking or recreational purposes) previously contaminated by birds during the migratory season may facilitate infections of humans through water. However, it is unclear how much wild waterfowl contribute to the transmission of giardiasis, cryptosporidiosis, cyclosporosis, and microsporidiosis in many regions through contaminated environmental sources. Comprehensive epidemiological surveillance based on molecular data on gastrointestinal pathogens is crucial to take measures to control infections in the future.

Molecular and phylogenetic characterization of Cryptosporidium species in the saffron finch Sicalis flaveola

BACKGROUND

Cryptosporidium is the most common protozoan that can infect a wide variety of animals, including mammals and birds. Fecal samples of six saffron finches, Sicalis flaveola, from a commercial establishment were screened for the presence of Cryptosporidium by the modified Ziehl-Neelsen technique and nested PCR of the 18S rRNA gene followed by sequencing of the amplified fragments.

RESULTS

The species Cryptosporidium galli was identified in all six saffron fiches, in addition to Cryptosporidium andersoni in one of the birds, indicating a mixed infection. Only two birds had feathers that were ruffled and dirty with feces. Concomitant infection with Isospora spp. was observed in all birds.

CONCLUSIONS

Saffron finches are a possible host of C. andersoni and this is the first report of this species in a captive bird and the third report of parasitism by C. galli in Sicalis flaveola.

Longitudinal surveillance of Cryptosporidium spp. in broiler chickens in Xinjiang, northwest China: genetic diversity of Cryptosporidium meleagridis subtypes

Cryptosporidium spp. are common enteric parasites in humans and animals. Herein, 175 faecal specimens were collected from a broiler farm in Xinjiang, China, including seven repeated samplings at 10-day intervals of broilers aged 10 to 70 days. Cryptosporidium was detected and identified by PCR-RFLP analysis. The overall infection rate of Cryptosporidium in broilers was 23.4% (41/175), with the highest infection rate of 48.0% (12/25) at 40 days of age, and no infection was detected at 10 days of age. Two Cryptosporidium species were confirmed, namely, C. baileyi (3.4%, 6/175) and C. meleagridis (20%, 35/175). In total, 21 of 35 C. meleagridis isolates were successfully subtyped based on the gp60 gene, and one known subtype, IIIgA22G3R1 (n = 1), and three novel subtypes, IIIbA25G1R1 (n = 10), IIIgA24G3R1 (n = 9) and IIIgA25G2R1 (n = 1), were identified. Our findings highlight the genetic diversity of C. meleagridis in Xinjiang and the potential endemic characteristics of the subtypes.

An Update on Zoonotic Cryptosporidium Species and Genotypes in Humans

The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and >120 genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and amplicon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.