Cryptosporidium is a microscopic protozoan that is disrupting public health care in half of Europe. The incidence of this digestive system parasite, which usually causes mild gastrointestinal distress – although it can be severe in babies due to dehydration and poses a life-threatening risk to immunocompromised people – has skyrocketed across much of the continent, with no solution from experts have found . a single cause that explains it. Spain has registered 2,940 confirmed cases so far this year, a number that multiplies the 805 cases registered in all of 2022, 121 of which required hospitalization, according to the National Center for Epidemiology. A similar trend to that in the United Kingdom, Ireland, the Netherlands and Luxembourg, according to recent publications from the European Center for Disease Control and Prevention (ECDC).
The detection of the parasite in recent weeks in more than 600 British and Irish tourists after a holiday in Spain has activated European warning systems but has also raised some concerns among Spanish researchers and public health officials. The reason lies in the way countries such as Ireland have presented the increase in cases, pointing to Spanish cities such as Salou (Tarragona) as a source of infection, where it is advisable to “not consume drinks with ice” and “to check whether the water “is being treated” in the tap, among other things. “Smell it to identify the smell of chlorine bleach,” the country’s health ministry said in a statement.
In reality, health officials from two autonomous communities familiar with epidemiological investigations point out that “the focus of this type of contagion is often the hotel pools, where dozens or hundreds of people of the same nationality gather, some of whom arrive infected and.” where all hygiene measures are not always observed, which favors outbreaks among tourists themselves.” These sources emphasize that “cryptosporidiosis [la enfermedad causada por el parásito] “It is a global problem and the way the problem is sometimes addressed is far from reality and does not focus on the measures that really help prevent infections.”
An example often cited among professionals is the Irish authorities’ recommendation that in case of diarrhea “not to enter swimming pools for two days after the symptoms have disappeared”, although in these cases swimming should be avoided for 14 days.
Cryptosporidia is actually a large genus of protozoa that affects dozens of species of mammals, birds, and reptiles. Although each parasite has a greater affinity for a particular species, jumps between them often occur. The protozoan enters the host’s intestinal epithelium by consuming contaminated water or food. There the parasite reproduces after several phases and forms tens of thousands of oocysts, which are released into the environment through the feces. These oocysts are often resistant to the chlorine concentrations in drinking water networks and swimming pools. This and the fact that just a dozen of them are enough to make a person sick explain the frequency and extent of the outbreaks.
Infections in humans usually occur in two ways. The first reason is due to the pollution of drinking water networks or facilities such as swimming pools, a process favored by episodes such as torrential rains. According to Isabel de Fuentes, a parasitology researcher at the National Center of Microbiology of the Carlos III Health Institute, in these cases “water treatment systems and plants may be overloaded” or there may be a carryover effect from oocysts distributed in the environment or on other farms. Cattle.
This appears to be the cause of the major outbreak that has occurred in Tarazona (Zaragoza) in recent months, involving more than 500 cases, the specific cause of which is still under investigation. The largest epidemic of these characteristics recorded in the scientific literature occurred in April 1993 in Milwaukee (USA), affecting more than 400,000 people – a quarter of the metropolitan area’s population – with 69 deaths when the drinking water network was interrupted.
The second major form of infection is between people and usually occurs in closed water facilities, explains Jacob Lorenzo-Morales, director of the protozoa laboratory at the University Institute of Tropical Diseases and Public Health of the Canary Islands and with experience in investigating Cryptosporidium outbreaks. “Swimming pools and water parks are a recurring source of outbreaks, but the fact that they occur has more to do with the hygiene of some users than with the cleanliness of these spaces, which are subject to strict maintenance regulated by regulations,” he explains .
“If someone does not clean themselves thoroughly after using the toilet or goes to the swimming pool after having diarrhea without following the recommended 14 days, thousands of oocysts are released into the water. If this is done by one or two people, chlorine and dispersion problems will not occur. But if there are several, or an infected baby with dirty diapers is in the water or similar events, the pool becomes contaminated,” describes Lorenzo-Morales.
The Health Alerts and Emergencies Coordination Center (CCAES) of the Ministry of Health confirms in writing that this year “there has been an increase in cases of Cryptosporidium reported by the Autonomous Communities, as well as by Ireland and the United Kingdom.” The center’s response continues : “The majority [de casos y brotes] They are primarily associated with swimming pools and recreational waters during the summer.” Given the increase noted, Health has “formed a working group with communities to improve environmental monitoring of this protozoan.”
Irish authorities released the statement on October 13, warning of a rise in cases of “cryptosporidiosis, a potentially serious stomach disease reported in areas of Spain, particularly in Salou in Catalonia,” and calling for “dietary precautions and nutrition “offered water to stay safe.” Data provided by the country’s health surveillance center shows that 64 cases linked to Salou have been diagnosed since August, including five hospitalizations, adding that the country has more this year has registered more than 650 cases of the disease, 30% more than in 2022.
However, that information did not specify how many cases or outbreaks occurred in the country among people who did not travel abroad. This is a relevant fact considering that the ECDC’s most recent annual report on the disease in Europe was published in 2021 with data from 2018 – making the country the country with the second highest incidence of cryptosporidiosis in the EU. A reckoning that experts should view with caution, however, because the disease is significantly underreported and not all countries have the same level of surveillance or report the same data to the agency.
An ongoing investigation by UK researchers, whose initial findings have been published in Eurosurveillance, the ECDC’s scientific journal, describes an “unusual increase” in cases of cryptosporidiosis in the country and distinguishes between cases acquired in the UK and those acquired abroad. A total of 2,411 cases of the disease were diagnosed in the UK between August 14 and October 1. Of them, just over half of those with information had reported traveling abroad, of which 46% – around a quarter of the total, around 600 – to Spain.
This leads the authors to state that the data “suggests that many cases may be linked to international travel, particularly to Spain and other Mediterranean countries,” although they also admit that “at this point in the investigation, it cannot be ruled out It is possible that other sources, such as contaminated food, contribute to the “overwhelm” of diagnoses. In any case, the researchers emphasize “the importance of avoiding the use of swimming pools.” [la persona] suffer from symptoms [gastrointestinales] and in the 14 days after its end.”
Another conclusion can be drawn from reading the work: the risk is not so much when traveling, but rather when bathing in contaminated pools. “The fact that half of those infected in the UK have not traveled outside the country is significant,” emphasizes De sources.
This expert believes that summer excursions and activities – during which tourism in Spain has increased significantly – are important key factors to take into account when interpreting the published data. “In the summer, people travel more and swim in swimming pools more, so it is logical that when and where this happens, more outbreaks will occur.” Without a complete and detailed study of the health situation and genotypes before and after travel, this can happen “It cannot be determined whether the origin of the outbreaks is in Spain or whether the parasite traveled with tourists from their countries of origin,” he concludes.
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