Category Archives: Cryptosporidium

Research – Transmission of Cryptosporidium by Fresh Vegetables

Journal of Food Protection

water contamination

Consumption of fresh fruits and vegetables is increasing thanks to the awareness to the benefits to human health. Vegetables may become contaminated by enteric pathogens (protozoan parasites, bacteria and viruses) by irrigation with contaminated water, fertilization with fresh animal manure or by infected food handlers. Cryptosporidium spp. are fecal-oral protozoan parasites, known to be highly persistent in the environment, which facilitate the transmission of the infectious oocysts. Efficient methods were developed for releasing and concentrating Cryptosporidium oocysts from leafy vegetables and sensitive and specific methods were applied for their enumeration. The aims of this review are to discuss the development and optimization of methods applied to release oocysts from leafy vegetables, the prevalence of Cryptosporidium oocysts on fresh leafy vegetables from various parts of the world and to discuss cryptosporidiosis outbreaks resulting from the consumption of leafy vegetables. Three solutions were used with comparable efficiency to release oocysts from leafy vegetables 1M glycine solution, 0.1% Alconox and filter elution buffer with an efficiency of 36.2%, 72.6% and 44%, respectively. The prevalence of Cryptosporidium oocysts was reported in developed as well as from developing countries, although simple detection methods were applied. Most of the cryptosporidiosis outbreaks were reported in developed countries, which can be related to their efficient surveillance system. Transmission of infectious pathogens, such as Cryptosporidium may be facilitated by fresh vegetables, which are imported and transferred from less developed to highly developed countries and consumed uncooked. Monitoring of Cryptosporidium oocysts by sensitive detection methods may enhance measures to prevent their transmission by freshly consumed vegetables.

Research – An outbreak of cryptosporidiosis associated with drinking water in north-eastern Italy, August 2019: microbiological and environmental investigations



The enteric parasite , along with norovirus,  and rotavirus, is among the most frequent causes of waterborne disease [1,2]. In humans, transmission of  occurs via the faecal-oral route, either through direct exposure to infected people (person-to-person infection) or animals (animal-to-person infection), or through ingestion of water (drinking water, recreational water such as swimming pools, water parks, lakes, rivers) or consumption of raw or undercooked food contaminated with infectious oocysts [3]. Infection may remain asymptomatic or manifest as acute gastroenteritis (> 80% of infected individuals). Symptoms occur 1 to 12 days (mean: 7 days) after exposure and usually last 6 to 9 days. The severity and duration of symptoms are linked to the immune status of the host, and cryptosporidiosis can be life threatening in immunosuppressed individuals [4].

There are many  species that can infect humans, but the vast majority of cases are due to , a zoonotic species that also infects young ruminants, and , which is essentially only a human pathogen [5]. The environmental route of transmission is of high relevance for  [6]. This is due to several factors including: (i) the high survival rate of oocysts in water (more than 24 months at 20°C), (ii) high resistance to disinfection (30 mg/L of free chlorine are needed to achieve 99% inactivation at pH 7, with a recommended value of 0.2 mg/L for drinking water) [6], (iii) low infectious dose (10–132 oocysts in healthy adults [7]) and (iv) low host specificity [5]. Oocysts lose their infectivity when frozen, boiled or heated over 60°C [6].

The ability of  to survive at high chlorine concentrations [8] and, consequently, at the disinfectant concentrations commonly used in water treatment, has always been a challenge for water treatment plant operators. However, other disinfectants, such as chlorine dioxide, ozone, UV rays and filtration have proved to be rather effective in removing . Water safety mainly depends on the combination of different treatment stages, and a multi-barrier approach is a key paradigm for ensuring safe drinking water [6]. Nonetheless, in small water supplies managed by local communities that serve only few thousand people, multi-barrier treatment systems are usually not implemented. Thus, in order to ensure the safety of drinking water, more traditional treatments, e.g. disinfection, are used and water quality is checked against certain regulatory parameters.

During 2017–20, 60 waterborne outbreaks of cryptosporidiosis have been detected in Europe, the majority of which involving treated recreational water (swimming pools) as the vehicle of infection [9]. The number of outbreaks linked to contaminated drinking water has shown a notable decrease in the past decades, although, when occurring, large numbers of individuals may be involved, as exemplified by the outbreaks reported in 2010–11 in Sweden [10,11].

Ireland – Potentially dangerous parasite in County Limerick water supply – Cryptosporidium

Limerick Post

DRINKING water supplies in Foynes have come under the microscope with the ongoing detection of a parasite that could pose a threat to human health.

Cryptosporidium, a parasite found in human and animal faeces, has been detected in the Foynes/Shannon Estuary water treatment plant this year.

The Environmental Protection Agency said it was “very concerned” after it conducted an audit which detected two breaches of recommended limits of cryptosporidium at the plant on February 23 and April 13.

The EPA said that it was most likely due to “a deterioration in raw water quality combined with significant deficiencies and pressures on the treatment processes at the plant”.

The environmental watchdog said the incident was suitably escalated and managed to protect the health of the population of over 7,200 in the Foynes area who use the water supply.

Research – Pathogens can hitch a ride on plastic to reach the sea

Phys Org

Microplastics are a pathway for pathogens on land to reach the ocean, with likely consequences for human and wildlife health, according to a study from the University of California, Davis.

The study, published April 26 in the journal Scientific Reports, is the first to connect microplastics in the ocean with land-based pathogens. It found that microplastics can make it easier for disease-causing pathogens to concentrate in plastic-contaminated areas of the ocean.

The pathogens studied—Toxoplasma gondii, Cryptosporidium (Crypto) and Giardia—can infect both humans and animals. They are recognized by the World Health Organization as underestimated causes of illness from shellfish consumption and are found throughout the ocean.

“It’s easy for people to dismiss plastic problems as something that doesn’t matter for them, like, ‘I’m not a turtle in the ocean; I won’t choke on this thing,'” said corresponding author Karen Shapiro, an infectious disease expert and associate professor in the UC Davis School of Veterinary Medicine. “But once you start talking about disease and health, there’s more power to implement change. Microplastics can actually move germs around, and these germs end up in our water and our food.”

Research – Cryptosporidium: Still Open Scenarios


water contamination

Cryptosporidiosis is increasingly identified as a leading cause of childhood diarrhea and malnutrition in both low-income and high-income countries. The strong impact on public health in epidemic scenarios makes it increasingly essential to identify the sources of infection and understand the transmission routes in order to apply the right prevention or treatment protocols. The objective of this literature review was to present an overview of the current state of human cryptosporidiosis, reviewing risk factors, discussing advances in the drug treatment and epidemiology, and emphasizing the need to identify a government system for reporting diagnosed cases, hitherto undervalued.

Research -Surveillance of berries sold on the Norwegian market for parasite contamination using molecular methods

Science Direct

water contamination

The risk of foodborne parasite infection linked to the consumption of contaminated fresh produce has long been known. However, despite epidemiological links between the outbreaks and contaminated berries, few studies have assessed the magnitude of parasite contamination on fresh produce sold in Europe. The present study was aimed to address the knowledge gap on parasite contamination of berries sold in Norway. Samples of blueberries, strawberries, and raspberries were analysed by multiplex qPCR for detection of Echinococcus multilocularisToxoplasma gondii, and Cyclospora cayetanensis. In addition, a simplex qPCR method was employed for detecting contamination of the berries with Cryptosporidium spp. A total of 820 samples of berries, each of around 30 g (274 samples of blueberries, 276 samples of raspberries, and 270 samples of strawberries), were analysed. We found an overall occurrence of 2.9%, 6.6%, and 8.3% for T. gondii, C. cayetanensis, and Cryptosporidium spp., respectively, whereas E. multilocularis was not detected from any of the samples investigated. Strawberries and raspberries were most often contaminated with Cryptosporidium spp., whereas blueberries were contaminated mostly with C. cayetanensis. Detection of parasite contaminants on fresh berries indicates the need for a system to ensure the parasitological safety of fresh berries.

UK – Estimating deaths from foodborne disease in the UK for 11 key pathogens



To estimate the number of deaths from foodborne disease in the UK from 11 key pathogens.


Four different models were developed using data from a range of sources. These included enhanced surveillance, outbreaks, death certificates and hospital episode statistics data. For each model, median estimates were produced with 95% credible intervals (CrI). The results from the different models were compared.


The estimates for foodborne deaths for each pathogen from the different models were consistent, with CrIs largely overlapping. Based on the preferred model for each pathogen, foodborne norovirus is estimated to cause 56 deaths per year (95% CrI 32 to 92), foodborne Salmonella 33 deaths (95% CrI 7 to 159), foodborne Listeria monocytogenes 26 deaths (95% CrI 24 to 28), foodborne Clostridium perfringens 25 deaths (95% CrI 1 to 163) and foodborne Campylobacter 21 deaths (95% CrI 8 to 47). The considerable overlap in the CrIs means it is not possible to make any firm conclusions on ranking. Most of these deaths occur in those aged over 75 years. Foodborne deaths from ShigellaCryptosporidiumGiardia, adenovirus, astrovirus and rotavirus are all rare.


We estimate that there are 180 deaths per year in the UK (95% CrI 113 to 359) caused by foodborne disease based on these 11 pathogens. While this is a small fraction of the estimated 2.4 million cases of foodborne illness per year it still illustrates the potential severity of these illnesses demonstrating the importance in continuing efforts to reduce these infections.

Keywords: infectious disease, CampylobacterSalmonella

Summary box

What is already known about this subject?

  • Foodborne disease is a common illness in the UK.

  • Previous research has estimated that there are 566 000 cases, 74 000 general practitioner presentations and 7600 hospital admissions related to foodborne disease from 13 known pathogens in UK; no estimate was made for deaths.

  • Campylobacter and norovirus are the most common foodborne pathogens in the UK.

  • Other common foodborne pathogens include Clostridium perfringens and Salmonella.

What are the new findings?

  • This study provides updated estimates of deaths for each of the 11 key foodborne pathogens considered; in total, these 11 pathogens cause 180 deaths per year in the UK (95% credible interval (CrI) 113 to 359).

  • Among them, Campylobacter, C. perfringens, Listeria monocytogenes, Salmonella and norovirus pathogens are responsible for over 98% of these deaths.

  • Ranking between these five is difficult due to overlapping CrIs.

How might it impact on clinical practice in the foreseeable future?

  • This highlights the potential severity of Salmonella, L. monocytogenesC. perfringensCampylobacter and norovirus, particularly in comparison with other infectious intestinal diseases that have a food source.

Ireland – Councillor hopeful north Kerry boil water notice could be lifted this week – Cryptosporidium

water contamination

Radio Kerry

A Kerry county councillor says it’s hoped a boil water notice affecting 3,500 people for over a month could be lifted later this week.

On October 11th, the HSE issued a boil water notice for people supplied by the Ardfert North/Ballyheigue scheme, following the detection of cryptosporidium.

Irish Water is currently installing a UV system, which is now being commissioned before the matter is referred back to the HSE.

Ireland – Upgrade works completed on North Kerry treatment plant under boil water notice

Radio Kerry

Upgrade works have been carried out on a North Kerry treatment plant, which serves an area that’s been under a boil water notice for four weeks.

The notice for the Ardfert North (Ballyheigue) Public Water Supply was put in place on October 11th due to the detection of cryptosporidium in the public water supply.

Irish Water says 3,500 people are impacted by this boil water notice, which remains in place.

Ireland – Boil water notice issued for thousands in Co Longford – Cryptosporidium

Irish Times


Almost half of the population of Co Longford is subject to a boil water notice which was issued on Thursday.

It comes after the cryptosporidium barrier at a treatment plant was compromised following a deterioration in the raw water quality of the lake source, Irish Water said.

Following consultation with the HSE, Irish Water and Longford County Council decided to issue a boil water notice for the area supplied by the Longford Central Public Water Supply to protect public health.

The population impacted by this notice is approximately 17,500 people. The areas affected include all customers in Longford Town, Newtown Forbes, Balinalee, part of Edgeworthstown, part of Drumlish, part of Killashee and surrounding areas.

Experts from Irish Water and Longford County Council are assessing the situation with a view to having the notice lifted as quickly as possible. In the meantime, all customers of this supply are advised to boil water before use until further notice.