Cryptosporidium parvum causes gastroenteritis epidemics in the Nablus region of Palestine

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 selected intestinal protozoan infections in marginalized rural communities in Palestine

Background

Intestinal parasitic infections are common in rural areas with poor infrastructure and low socioeconomic status. The aim of this study was to estimate the prevalence of selected parasitic infections in marginalized rural areas in the northern part of the Palestinian West Bank Region, using conventional and PCR-based methods, and also to assess risk predictors of infection.

Methods

A cross-sectional study was conducted on 104 individuals from three rural villages in the Jordan Valley. Stool samples were collected and examined by a battery of tests that included microscopy of wet fecal samples in normal saline with iodine, concentration by ethyl acetate sedimentation and also by zinc sulfate floatation, a conventional PCR and a real-time PCR (qPCR). Risk factors were assessed that included demographic, socioeconomic, and behavioral characteristics. Data on method performance was analyzed by kappa-statistic, Cochrane’s Q, and McNemar post hoc test. Mid-P exact test and odds ratio were used to discern association between outcome and risk predictors.

Results

The overall prevalence of intestinal parasitic infections was 48% (49/102). The predominant parasites were Giardia lamblia at 37% (37/102) and Hymenolepis nana at 9% (9/102). To concentrate cysts and eggs, sedimentation can be used as an alternative to floatation with a loss of 1% of positive cases. The methods employing PCRs proved crucial as it increased the detected infection rate of G. lamblia approximately three-fold from 13% by the conventional methods to 37% by the qPCR. Multiple infections were present in 13% (13/102) of the study group, which included double (10%) and triple (3%) infections. Regarding the genus Entamoeba, E. dispar and E. coli were detected at rates of 2 and 8%, respectively. While none of the individuals were infected with the pathogenic E. histolytica, E. nana (4%) was detected for the first time in the area. Age was a risk predictor for infection (OR = 2.61, CI 95% 1.05–6.45, P = 0.038).

Conclusions

The increased prevalence of intestinal parasitic infections in children in marginalized rural areas in Palestine is worrying. The addition of PCR-based methods is important for the diagnosis of such infections as, with cautious interpretation, it increases proficiency and overcomes underestimation and misdiagnosis of cases. Control measures including education on personal hygiene and environmental sanitation, should be introduced to reduce the prevalence of the intestinal parasites and, thus, the infections they cause in this and other areas.

An evaluation of the potential use of Cryptosporidium species as agents for deliberate release

INTRODUCTION

We evaluated the potential of Cryptosporidium spp. for intentional transmission as a terrorist tactic in asymmetric conflicts in terms of the recognised optimum conditions for biological warfare.

METHODS

Published and widely accepted criteria regarding the optimum conditions for the success of biological warfare based on experience from passive biological warfare research were applied to hypothetical intentional Cryptosporidium spp. transmission.

RESULT

The feasibility of the use of Cryptosporidium spp. transmission for terrorist purposes was established. Particularly on tropical deployments with poor hygiene conditions, such attacks might have a good chance of remaining undetected as a deliberate terrorist attack.

CONCLUSIONS

Intentional transmission should be suspected in cases of sudden outbreaks of cryptosporidiosis, particularly where adequate food and drinking water hygiene precautions are being enforced. Appropriate diagnostic procedures should be available so that the diagnosis is not missed.

Cryptosporidium in countries of the Arab world: the past decade (2002-2011)

Introduction

Cryptosporidium is the causative agent of cryptosporidiosis. The disease is self-limited in immunocompetent persons but potentially life-threatening in immunocompromised individuals.

Methods

The data included in the present review were obtained mainly from a Highwire Press (including PubMed) search for the period 2002–2011.

Results

Information on cryptosporidiosis is lacking in some Arab countries; however available data show prevalence rates of <1–43% (mean = 8.7%) of Cryptosporidium infection in diarrheic immunocompetent pediatrics and <1–82% (mean 41%) in immunocompromised patients (including children and adults). Infection rate with Cryptosporidium species among pediatrics in rural and semiurban areas was higher than in urban areas. Cryptosporidium-associated diarrhea occurs mainly in younger children and inversely correlates with age, being more prevalent in children aged 1 year or less, particularly in rural and suburban regions. Although most Arab countries are characterized by a hot summer and a mild winter, infection with Cryptosporidium appears to occur at a higher rate of incidence during the rainy months that are usually associated with the cold season of the year. Contact with animals and contaminated waters are the main modes of transmission of cryptosporidia. Reports of C. hominis from the region indicate that person-to-person transmission is also important. Foreign housekeepers in oil-rich countries may be a source of Cryptosporidium.

Conclusion

Cryptosporidium species, mainly C. parvum, are important causes of diarrhea in countries of the Arab world, particularly in children. In addition to educational programs that promote personal, household, as well as food hygiene, improving water treatment processes and protection of treated waters from contamination should be implemented by the health and environmental authorities in each country. More studies employing molecular testing methods are needed in the future to provide data on circulating species/genospecies and subtypes and their modes of transmission in the community.