Cryptosporidium genotypes and subtypes distribution in river water in Iran

Cryptosporidium and agriculture: A review

Cryptosporidiosis is a significant contributor to global foodborne and waterborne disease burden. It is a widespread cause of diarrheal diseases that affect humans and animals worldwide. Agricultural environments can become a source of contamination with Cryptosporidium species through faecal material derived from humans and animals. This review aims to report the main findings of scientific research on Cryptosporidium species related to various agricultural sectors, and highlights the risks of cryptosporidiosis in agricultural production, the contamination sources, the importance of animal production in transmission, and the role of farmed animals as hosts of the parasites. Agricultural contamination sources can cause water pollution in groundwater and different surface waters used for drinking, recreational purposes, and irrigation. The application of contaminated manure, faecal sludge management, and irrigation with inadequately treated water are the main concerns associated with foodborne and waterborne cryptosporidiosis related to agricultural activities. The review emphasizes the public health implications of agriculture concerning the transmission risk of Cryptosporidium parasites and the urgent need for a new concept in the agriculture sector. Furthermore, the findings of this review provide valuable information for developing appropriate measures and monitoring strategies to minimize the risk of infection.

Prevalence and molecular analysis of Cryptosporidium spp. collected from surface water

Cryptosporidium is an obligate intracellular parasite reported from all over the world. This protozoan infects a wide range of animals as well as humans. Cryptosporidium parvum and Cryptosporidium hominis are the most prevalent infecting species with mild and self-limiting infection in healthy people. The protozoan oocyst is resistant to common water purifiers. Based on emerging evidence, Cryptosporidium is one of waterborne parasites considered a major public health problem in developing and developed countries. In this study, 42 samples were collected from 14 rivers in the catchment area of Lake Urmia in northwest of Iran. Moreover, amplification of SSU rRNA gene was performed, and polymerase chain reaction products were sequenced. The results of sequencing and comparing the sequences with those in the GenBank revealed that all the 17 positive samples were C. parvum, a zoonotic species and one of the most frequent human-infecting species. Considering these data, it is highly important to inhibit the spread of this protozoan by treating livestock and preventing human and animal effluents from entering the water.

A review of the molecular epidemiology of Cryptosporidium spp. and Giardia duodenalis in the Middle East and North Africa (MENA) region

Cryptosporidium spp. and Giardia duodenalis are important protozoan parasites which are associated with diarrheal diseases in humans and animals worldwide. Relatively little is known about the molecular epidemiology of Cryptosporidium spp. and Giardia duodenalis in the Middle East Countries and North Africa (MENA region). Therefore, this review aimed to inspect published genotyping and subtyping studies on Cryptosporidium spp. and Giardia duodenalis in the MENA region. These studies indicate that both anthroponotic and zoonotic transmission of Cryptosporidium occurs with the predominance of zoonotic transmission in most countries. Seven Cryptosporidium species were identified in humans (C. parvum, C. hominis, Cryptosporidium meleagridis, C. felis, Cryptosporidium muris, C. canis and C. bovis), with C. parvum by far being the most prevalent species (reported in 95.4% of the retrieved studies). Among C. parvum gp60 subtype families, IIa and IId predominated, suggesting potential zoonotic transmission. However, in four MENA countries (Lebanon, Israel, Egypt and Tunisia), C. hominis was the predominant species with five subtype families reported including Ia, Ib, Id, If and Ie, all of which are usually anthroponotically transmitted between humans. In animals, the majority of studies were conducted mainly on livestock and poultry, 15 species were identified (C. parvum, C. hominis, C. muris, Cryptosporidium cuniculus, C. andersoni, C. bovis, C. meleagridis, C. baileyi, C. erinacei, C. ryanae, C. felis, C. suis, Cryptosporidium galli, C. xiaoi and C. ubiquitum) with C. parvum (IIa and IId subtypes) the dominant species in livestock and C. meleagridis and C. baileyi the dominant species in poultry. With G. duodenalis, five assemblages (A, B, C, E and F) were identified in humans and six (A, B, C, E, D and F) in animals in MENA countries with assemblages A and B commonly reported in humans, and assemblages A and E dominant in livestock. This review also identified a major knowledge gap in the lack of Cryptosporidium spp. and Giardia duodenalis typing studies in water and food sources in the MENA region. Of the few studies conducted on water sources (including drinking and tap water), ten Cryptosporidium species and four genotypes were identified, highlighting the potential role of water as the major route of Cryptosporidium spp. transmission in the region. In addition, three G. duodenalis assemblages (A, B and E) were detected in different water sources with AI, AII and BIV being the main sub-assemblages reported. More research is required in order to better understand the molecular diversity and transmission dynamics of Cryptsporidum spp. and Giardia duodenalis in humans, animals, water and food sources in MENA region.

Prevalence of Cryptosporidium spp. in water: a global systematic review and meta-analysis

Cryptosporidium spp., as a genus of protozoan intestinal parasites, is recognized as responsible for cryptosporidiosis. The present study was conducted to provide an overview of the prevalence of Cryptosporidium based on water. In this regard, some databases such as Scopus, PubMed, Embase, and Web of Science were screened in order to retrieve the related citations from 1 January 1983 to 10 September 2019. The pooled prevalence of Cryptosporidium spp. was calculated by using a random effect model (REM) based on defined subgroups, including countries, water type, treatment conditions (treated and untreated), economic condition, World Health Organization (WHO) regions, and method of detection. In contrast, this index for treated and untreated water was 25.7% and 40.1%, respectively. Also, the overall prevalence of Cryptosporidium spp. among all water types was defined as 36 (95% CI: 31.4-40.7). The rank order of prevalence of Cryptosporidium spp. based on water type was wastewater (46.9%) > surface water (45.3%) > raw water (31.6%) > drinking water (25.5%) > reservoirs water (24.5%) > groundwater (18.8%) > swimming pool water (7.5%) > marine water (0.20%). Identifying the key contributing factors to Cryptosporidium spp. survival can help provide solutions at both local and global scales.

Report of Giardia assemblages and giardiasis in residents of Guilan province-Iran

Giardia duodenalis is considered a highly diverse organism that infects a variety of mammalian hosts. Giardiasis is a significant public health problem in Iran. The purpose of this study was to investigate the occurrence of Giardia duodenalis (G. lamblia, G. intestinalis) infections in humans residing in the Guilan province of Iran. Stool samples were collected during 12 months from 8356 individuals that had been referred to certain hospitals in the capital city of Rasht in the Guilan province, of which 4126 were males and 4230 were females. The samples were separated into three groups according to patient age: group A 1-9 years old (n = 483); group B 10-19 years old (n = 491); and group C greater than 20 years old (n = 7382). The wet mount technique was performed directly on 8356 fecal samples for microscopy. Samples were examined using a saline and iodine direct smear technique in order to confirm the presence of G. duodenalis. The results indicated that 2.5% (206/8356) of the samples were identified as positive for G. duodenalis. A total of 30% of the infected patients (n = 62) had no symptoms. In symptomatic cases, the most common symptoms (46%, n = 95) were abdominal cramps and bloating. Twenty-four percent of patients (n = 50) had cramps, bloating, nausea, and diarrhea. Sixty positive samples were sent for G. duodenalis genotyping based on the amplification of the gdh gene. Forty-one PCR products were successfully selected and sequenced, where 38 (92.6%) samples were identified as genotype A/subgenotype II and in three samples (7.4%) genotype B/subgenotype IV. Genotype A-II had a dominant prevalence as compared to the genotype B-IV samples that were identified in the study. Based on the samples provided by the regional teaching hospitals and subsequent sample analysis, the authors concluded that assemblage A-II is most likely the most common Giardia subgroup infection in the Guilan region. Assemblages have been reported in both humans and animals; however, further studies need to investigate the role of domestic animals and water reservoirs as potential sources of Giardia infection in the Guilan region.

Optimizing the performance of conventional water treatment system using quantitative microbial risk assessment, Tehran, Iran

The performance of conventional drinking water treatment plants (WTPs) can be improved using quantitative microbial risk assessment (QMRA). A QMRA study on Cryptosporidium using actual pathogen density was conducted to examine the performance of Jalaliyeh WTP in Tehran, Iran. The infection risk and the burden of disease attributed to the parasite presence in finished water were estimated incorporating physical and chemical log reduction values (LRVs), using stochastic modeling and disinfection profiling. The risk and burden of disease were compared with health-based targets, i.e. one case of infection per 10,000 people or 10^-6 DALYs per person per year. The parasite's LRVs were 2.31 and 0.034 log provided by physico-chemical treatment and disinfection processes, respectively. The mean of estimated risk (111 cases per 10⁴ people per year) and the burden of disease (11.7 DALYs per 10⁶ people per year) both exceeded the targets. To control the excess risk, three QMRA-based disinfection scenarios were examined including: (1) employing chlorine dioxide (ClO₂) instead of chlorine (2) ozonation with a concentration of 0.75 mg/L (Ct = 22.5 min mg/L) and (3) UV irradiation with a dose of 10 mJ/cm². The LRV of parasite may be increased to 3.0, 5.1 and 4.9 log by employing ClO₂, ozonation and UV irradiation, respectively. The use of ozone or UV as alternative disinfectants, could enhance the disinfection efficacy and provide sufficient additional treatment against the excess risk of parasite. QMRA could make it easier applying appropriate improvement to conventional WTPs in order to increase the system performance in terms of health-based measures.

Cryptosporidium and Giardia in Wastewater and Surface Water Environments

and spp. are significant contributors to the global waterborne disease burden. Waterways used as sources of drinking water and for recreational activity can become contaminated through the introduction of fecal materials derived from humans and animals. Multiple studies have reported the occurence or concentrations of these pathogens in the environment. However, this information has not been comprehensively reviewed. Quantitative microbial risk assessment (QMRA) for and can be beneficial, but it often relies on the concentrations in environmental sources reported from the literature. A thorough literature review was conducted to develop an inventory of reported and concentrations in wastewater and surface water available in the literature. This information can be used to develop QMRA inputs. and (oo)cyst concentrations in untreated wastewater were up to 60,000 oocysts L and 100,000 cysts L, respectively. The maximum reported concentrations for and in surface water were 8400 oocysts L and 1000 cysts L, respectively. A summary of the factors for interpretation of concentration information including common quantification methods, survival and persistence, biofilm interactions, genotyping, and treatment removal is provided in this review. This information can help in identifying assumptions implicit in various QMRA parameters, thus providing the context and rationale to guide model formulation and application. Additionally, it can provide valuable information for water quality practitioners striving to meet the recreational water quality or treatment criteria. The goal is for the information provided in the current review to aid in developing source water protection and monitoring strategies that will minimize public health risks.

Giardia duodenalis and Cryptosporidium spp. as contaminant protozoa of the main rivers of western Romania: genetic characterization and public health potential of the isolates

The objective of this study was to establish the prevalence, contamination level, and public health significance of Giardia duodenalis and Cryptosporidium spp. in the primary rivers of western Romania. A total of 53 sampling points in the 24 most important western Romanian rivers in four counties (Arad, Bihor, Caraș-Severin, and Timiș) were investigated from March to September 2016. Surface water samples were collected by microfiber filtration. Cryptosporidium and Giardia (oo)cysts were isolated using immunomagnetic separation (IMS) according to the USEPA 1623 method and, after staining with fluorescently labeled (FITC) monoclonal antibodies, were identified and counted under a microscope. The Cryptosporidium and Giardia (oo)cysts were identified to species and assemblage/sub-assemblage level through the nested PCR-RFLP procedure targeting the 18S ribosomal RNA and gdh genes, respectively. PCR-based techniques were utilized for all water samples. Overall, 22 samples (41.5%) were determined to be positive for Giardia cysts (ranging from 0.05 to 300 cysts per liter), and four samples (7.5%) tested positive for Cryptosporidium oocysts (0.17-48 oocysts/l). G. duodenalis was molecularly identified in 13 water samples (24.5%), indicating the presence of the sub-assemblage A-II (n = 12) and assemblage E (n = 1). PCR-RFLP showed that two samples (3.8%) contained Cryptosporidium DNA, and the identified species were Cryptosporidium parvum and Cryptosporidium canis. All positive results were successfully confirmed by DNA sequencing. Subtyping of the zoonotic C. parvum isolate based on sequence analysis of the GP60 gene revealed the occurrence of the IIaA16G1R1 subtype. The results of this study highlight considerable contamination of river waters with pathogenic Giardia spp. and Cryptosporidium spp., suggesting a potential risk for the public and animal health. This report presents the first extended published description of the presence of Giardia spp. and Cryptosporidium spp. in the aquatic environment in Romania.

Cryptosporidium species from common edible bivalves in Manila Bay, Philippines

Manila Bay is one of the major propagation sites of edible bivalves in the Philippines. Studies have shown that bivalves might be contaminated with human pathogens like the protozoan parasite Cryptosporidium, one of the major causes of gastroenteritis in the world. In this study, Cryptosporidium from four species of edible bivalves were isolated using a combination of sucrose flotation and immunomagnetic separation. Using direct fluorescent antibody test, Cryptosporidium oocysts were found in 67 out of 144 samples collected. DNA sequence analysis of the 18S rRNA gene of the isolates detected C. parvum and C. hominis (major causes of human cryptosporidiosis) and C. meleagridis (causes infection in avian species). Analysis of the 60kDa glycoprotein gene further confirmed the genotypes of the Cryptosporidium isolates. This study is the first to provide baseline information on Cryptosporidium contamination of Manila Bay where bivalves are commonly cultured.

Contribution of environmental media to cryptosporidiosis and giardiasis prevalence in Tehran: a focus on surface waters

The occurrences of Cryptosporidium and Giardia in surface sources of drinking water in Tehran were monitored, using US EPA method 1623.1. The prevalence ratios (PR) of positive samples among other media (animal's stools, vegetables, and human's stools) were also estimated from literature data. The density of Giardia and Cryptosporidium in water samples were 0.129 ± 0.069 cysts/L and 0.005 ± 0.002 oocysts/L, respectively. Estimated PR in vegetables, animal stools, surface waters, and human stools were 6.65, 20.42, 21.05, and 4.28 % for Cryptosporidium and 6.46, 17.13, 73.68, and 15.65 % for Giardia, respectively. These reveal the importance of surface waters' and animal stools' roles in the prevalence of cryptosporidiosis and giardiasis in Tehran's population. Giardia's prevalence in untreated surface waters in Tehran was found 3.5 times as much as Cryptosporidium while this found 2.3 times on a global scale. Moreover, the prevalence of giardiasis to cryptosporidiosis infections in Tehran's human population was 3.65. These values could be a clue to attribute the infections to the occurrence of parasites in surface waters. Significant (p < 0.05) associations were observed between rainfalls and presence of Giardia (r = 0.62) and Cryptosporidium (r = 0.60) in surface waters. In autumn, rainfalls can increase the parasites occurrences in surface waters. Significant (p < 0.05) difference on the density of parasites was found between some seasons using Kruskal-Wallis and multiple comparison tests. A significant correlation (r = 0.86) between Giardia and Cryptosporidium densities also confirms the common sources of pollution in surface waters. Findings suggest that untreated surface waters in Tehran may be a potential route of human exposure to protozoan parasites.

Public health significance of zoonotic Cryptosporidium species in wildlife: Critical insights into better drinking water management

Cryptosporidium is an enteric parasite that is transmitted via the faecal-oral route, water and food. Humans, wildlife and domestic livestock all potentially contribute Cryptosporidium to surface waters. Human encroachment into natural ecosystems has led to an increase in interactions between humans, domestic animals and wildlife populations. Increasing numbers of zoonotic diseases and spill over/back of zoonotic pathogens is a consequence of this anthropogenic disturbance. Drinking water catchments and water reservoir areas have been at the front line of this conflict as they can be easily contaminated by zoonotic waterborne pathogens. Therefore, the epidemiology of zoonotic species of Cryptosporidium in free-ranging and captive wildlife is of increasing importance. This review focuses on zoonotic Cryptosporidium species reported in global wildlife populations to date, and highlights their significance for public health and the water industry.