Scientists discover how Giardia makes people ill

One of my favorite pastimes is to go camping with the family and enjoy nature….in a cabin. I’m getting too old to tent and contend with the mosquitoes and bears. One thing is for sure, I avoid drinking water that hasn’t been treated due to the potential risk of parasites, in particular, Giardia.

BBC News reports

Now scientists say they have discovered how the parasites that cause giardiasis – one of the world’s most common gastric diseases – make people ill.
Giardia parasites mimic human cell functions to break apart cells in the gut and feed inside, researchers found.
This also allows bacteria already present in the body to join in and feed from the same nutrients, they said.
‘Ready meals’
Some 500,000 cases of giardiasis are diagnosed each year, with people typically picking up the disease by drinking infected water or contaminated food.
Symptoms include severe diarrhoea, stomach pains, bloating, flatulence and fatigue and can last weeks or months without treatment.
Although it is found throughout the world, it is most prevalent in developing countries and is one of the most common gastric diseases caught by backpackers.
But although scientists have known of giardia’s existence for hundreds of years, until now it remained unclear how it makes people sick.
Giardia parasites are picked up in infected water or contaminated food, usually in developing countries. 
Researchers found the giardia parasite produces two types of protein that enable it to cut through layers of protective mucus in the gut – breaking the links that knit cells together – in order to easily access the nutrients within them.
One of the proteins does this by mimicking a group of human proteins called tenascins, which regulate cell adhesion and break apart when necessary, such as during wound healing.
But the giardia tenascins are used instead to upset the body’s balance by preventing healing of the junctions between cells that hold them together.
One of the study’s authors, Dr Kevin Tyler, from UEA’s Norwich medical school, said: “Because the giardia have broken down the cell barriers and made all these nutrients available, other, opportunistic bacteria can move in to take advantage of these ‘ready meals’ which can make giardiasis even more severe for some.”
‘Bad bacteria’
Those suffering from giardiasis are usually able to recover from the illness with or without antibiotics.
However, about half of those who get the parasite experience no symptoms of the illness.
Dr Tyler said the difference in the severity of disease might be explained by the proportion of “good” and “bad” bacteria in the gut.
Those who become more ill may have a higher proportion of “bad bacteria” feeding off nutrients released by the giardia parasite, Dr Tyler said.
Dr Tyler told the BBC: “Some people have a gut that is predominantly full of quite good bacteria that doesn’t cause inflammation and illness and indeed may protect from it.
“What we think is that in people who have the bad bacteria, the pro-inflammatory bacteria, those start to use the nutrients that have been unleashed by the giardia.
“The giardia does the damage, allowing the nutrients to flow into the gut, and then if you have the wrong kind of bacteria you get this cycle of inflammation.”
This is why probiotic drinks and supplements – which populate the gut with good bacteria – are helpful in treating giardiasis, he said.
The study was published in the journal GigaScience.
How to avoid giardiasis
When abroad make sure to drink filtered or bottled water
Practice good hygiene
Avoid eating food that may be contaminated
Avoid water (drinking or recreational) that may be contaminated
Clean up after ill people and pets

 

Two stricken with Giardia in Norway

Many thanks to our Norwegian correspondent who reports that two people admitted to Haukeland Hospital have been diagnosed with Giardia infection.

“We have two confirmed cases, but it is possibly a third too. It is too early to say anything about the source of infection,” says Surveillance Authority in Bergen municipality Kari Stidal Øystese.

Bergen is sensitive to Giardia outbreaks because in autumn 2004, the drinking water was infected by the Giardia parasite and approximately 5,000 people from Bergen became sick, and many have suffered after-effects for years.

In 2006, a SINTEF report commissioned drainage systems related to the buildings at Knatten, Starefossen and Tarlebøveien, triggered the epidemic. Local authority Torgeir Landvik would blame the dog owners for the fact that thousands of mountain people were infected by Giardia in the fall of 2004. But in 2015, an expert group picked up the dog-kit theory. “Based on available knowledge, Giardia infection from humans is still the most likely cause of the outbreak of disease and long-term strokes,” said the group’s conclusion.

A large community outbreak of waterborne giardiasis- delayed detection in a non-endemic urban area

BMC Public Health, 2006, 6:141,   Karin Nygård, Barbara Schimmer, Øystein Søbstad, Anna Walde, Ingvar Tveit, Nina Langeland, Trygve Hausken and Preben Aavitsland, https://doi.org/10.1186/1471-2458-6-141

https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-6-141

Background

Giardia is not endemic in Norway, and more than 90% of reported cases acquire the infection abroad. In late October 2004, an increase in laboratory confirmed cases of giardiasis was reported in the city of Bergen. An investigation was started to determine the source and extent of the outbreak in order to implement control measures.

Methods

Cases were identified through the laboratory conducting giardia diagnostics in the area. All laboratory-confirmed cases were mapped based on address of residence, and attack rates and relative risks were calculated for each water supply zone. A case control study was conducted among people living in the central area of Bergen using age- and sex matched controls randomly selected from the population register.

Results

The outbreak investigation showed that the outbreak started in late August and peaked in early October. A total of 1300 laboratory-confirmed cases were reported. Data from the Norwegian Prescription Database gave an estimate of 2500 cases treated for giardiasis probably linked to the outbreak. There was a predominance of women aged 20–29 years, with few children or elderly. The risk of infection for persons receiving water from the water supply serving Bergen city centre was significantly higher than for those receiving water from other supplies. Leaking sewage pipes combined with insufficient water treatment was the likely cause of the outbreak.

Conclusion

Late detection contributed to the large public health impact of this outbreak. Passive surveillance of laboratory-confirmed cases is not sufficient for timely detection of outbreaks with non-endemic infections.

E.coli, Giardia and crypto: Beware the duck pond at NZ Botanical Gardens

Gisborne’s chief medical officer has warned parents that children do not have to be in contact with water to pick up bugs from dirty water at the Botanical Gardens.

botanical-garden-japaneseGisborne District Council this week confirmed the duck pond at the gardens contained E.coli, Giardia and Cryptosporidium.

Although a statement from GDC said someone would have to drink “a good amount” of water to get sick, medical officer of health Dr Margot McLean pointed out that was not the case.

“You don’t have to enter the pond or drink the pond water to pick up the bugs that can make you sick. You could also pick up the bugs by putting hands in the water or touching areas where there is duck poo.

“This shouldn’t put people off visiting the ducks, as long as extra care is taken with hand hygiene.

“Antibacterial wipes could be used immediately after leaving the area, however parents should supervise children washing their hands and use the 20/20 rule; 20 seconds to wash/20 seconds to dry on the return home.

“Any duck poo should be removed from shoes so that the poo doesn’t contaminate surfaces like floors, or hands.”

Better ways to monitor beaver fever

The current approach in the U.S. water industry for monitoring Cryptosporidium and Giardia has weaknesses that have contributed to the difficulty of interpreting resulting data. This often leads to potentially significant and dangerous misinterpretation. The purpose of this paper is to summarize information on which the conflicting conclusions on the occurrence and distribution of Cryptosporidium and Giardia have been based.

giardia_lambliaEffort is made to determine the most plausible and supportable interpretation. The objective is to provide a basis for rethinking the current approach to monitoring and management of Cryptosporidium and Giardia in water.

The importance of measuring recovery efficiency and reporting measurements of these organisms in terms of concentration to any quantitative application is emphasized. Data presentation to illustrate critical features of organism concentration levels and variation is reviewed. Analysis of major data sets resulting from the U.S. Environmental Protection Agency Information Collection Rule Supplemental Survey (USEPA ICR SS) and the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2) monitoring and other previously published relevant data sets is presented to illustrate key features of Cryptosporidium and Giardia occurrence in surface water and their universal geographic distribution. Current thinking emphatically requires revision.

Cryptosporidium and Giardia in water: reassessment of occurrence and significance

ASCE

Jerry E.Ongerth

http://ascelibrary.org/doi/abs/10.1061/(ASCE)EE.1943-7870.0001161

Giardia — beaver fever – can be serious

Although most individuals with a Giardia infection are asymptomatic, this pathogen is increasingly recognized as a cause of pathologies beyond the classical manifestations.

beaver.feverMorbidities associated with Giardia, including extra-intestinal manifestations and long-term consequences, have been identified increasingly over the past decades. The importance of this pathogen in terms of patient well-being and its effect on quality of life, due to being a continuing cause of patient discomfort and pain, has been highlighted .

Sequelae of giardiasis: an emerging public health concern

Angel A. Escobedo, Pedro Almirall, Sérgio Cimerman, Alfonso J. Rodríguez-Morales

International Journal of Infectious Diseases, August 2016, Volume 49, Pages 202-203, DOI: http://dx.doi.org/10.1016/j.ijid.2016.06.008

http://www.ijidonline.com/article/S1201-9712(16)31092-X/abstract

Beaver fever: Petting zoos, untreated water primary sources of Giardia at home and abroad

The purpose of this study is to determine how demographic and exposure factors related to giardiasis vary between travel and endemic cases.

beaver.feverExposure and demographic data were gathered by public health inspectors from giardiasis cases reported from the Region of Waterloo from 2006 to 2012. Logistic regression models were fit to assess differences in exposure to risk factors for giardiasis between international travel-related cases and Canadian acquired cases while controlling for age and sex. Multinomial regression models were also fit to assess the differences in risk profiles between international and domestic travel-related cases and endemic cases.

Travel-related cases (both international and domestic) were more likely to go camping or kayaking, and consume untreated water compared to endemic cases. Domestic travel-related cases were more likely to visit a petting zoo or farm compared to endemic cases, and were more likely to swim in freshwater compared to endemic cases and international travel-related cases. International travellers were more likely to swim in an ocean compared to both domestic travel-related and endemic cases.

These findings demonstrate that travel-related and endemic cases have different risk exposure profiles which should be considered for appropriately targeting health promotion campaigns.

Beaver_FeverA comparison of exposure to risk factors for giardiasis in non-travellers, domestic travellers and international travellers in a Canadian community, 2006–2012

Epidemiology and Infection, Volume 144, Issue 5, April 2016, pages 980-999, DOI: http://dx.doi.org/10.1017/S0950268815002186

L. Swirski, D. L. Pearl, A. S. Peregrine, and K. Pintar

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10216090&utm_source=Issue_Alert&utm_medium=RSS&utm_campaign=HYG

Beaver fever in U.S., 1971–2011

My friend was at his cabin near Algonquin Park (that’s in Canada) and twittered that his wife wanted to know if it was OK to use stream water to boil potatoes.

french.dont.eat.poopHe said sure, as long as you don’t mind the beaver poop.

We’ve had a long tradition of don’t eat poop, but if you do, make sure it’s cooked.

Giardia intestinalis is the leading parasitic aetiology of human enteric infections in the United States, with an estimated 1·2 million cases occurring annually. To better understand transmission, we analysed data on all giardiasis outbreaks reported to the Centers for Disease Control and Prevention for 1971–2011.

The 242 outbreaks, affecting ~41 000 persons, resulted from waterborne (74·8%), foodborne (15·7%), person-to-person (2·5%), and animal contact (1·2%) transmission. Most (74·6%) waterborne outbreaks were associated with drinking water, followed by recreational water (18·2%). Problems with water treatment, untreated groundwater, and distribution systems were identified most often during drinking water-associated outbreak investigations; problems with water treatment declined after the 1980s. Most recreational water-associated outbreaks were linked to treated swimming venues, with pools and wading pools implicated most often. Produce was implicated most often in foodborne outbreaks. Additionally, foods were most commonly prepared in a restaurant and contaminated by a food handler.

giardia-posterLessons learned from examining patterns in outbreaks over time can help prevent future disease. Groundwater and distribution system vulnerabilities, inadequate pool disinfection, fruit and vegetable contamination, and poor food handler hygiene are promising targets for giardiasis prevention measures.

Giardiasis outbreaks in the United States, 1971–2011

11.jan.16

Epidemiology and Infection

DOI: http://dx.doi.org/10.1017/S0950268815003040

E.A. Adam, J.S. Yoder, L.H. Gould, M.C. Hlavsa, and W. Gargano

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=10111419&fileId=S0950268815003040

 

Crypto and giardia take $5 billion bite out of NYC

Two tiny organisms present a big problem for New York City’s water department: cryptosporidium and giardia.

crypto.waterThe city has spent $5 billion over the last five years combatting these organisms, which can cause fatal illnesses in the sick and elderly and gastrointestinal problems for those with healthy immune systems.

“In the city’s east-of-Hudson Croton watershed, where development has encroached on watershed land, federal regulators forced the city to filter the water; hence the $3 billion Croton filtration plant that recently opened,” City Limits reported.

The plant itself was a giant, politically fraught project.

Beaver fever: Giardiasis surveillance, US 2011–2012

Problem/Condition: Giardiasis is a nationally notifiable gastrointestinal illness caused by the protozoan parasite Giardia intestinalis.

Reporting Period: 2011–2012.

beaver.feverDescription of System: Forty-four states, the District of Columbia, New York City, the Commonwealth of Puerto Rico, and Guam voluntarily reported cases of giardiasis to CDC through the National Notifiable Diseases Surveillance System (NNDSS).

Results: For 2011, a total of 16,868 giardiasis cases (98.8% confirmed and 1.2% nonconfirmed) were reported; for 2012, a total of 15,223 cases (98.8% confirmed and 1.3% nonconfirmed) were reported. In 2011 and 2012, 1.5% and 1.3% of cases, respectively, were associated with a detected outbreak. The incidence rates of all reported cases were 6.4 per 100,000 population in 2011 and 5.8 per 100,000 population in 2012. This represents a slight decline from the relatively steady rates observed during 2005–2010 (range: 7.1–7.9 cases per 100,000 population). In both 2011 and 2012, cases were most frequently reported in children aged 1–4 years, followed by those aged 5–9 years and adults aged 45–49 years. Incidence of giardiasis was highest in Northwest states. Peak onset of illness occurred annually during early summer through early fall.

Interpretation: For the first time since 2002, giardiasis rates appear to be decreasing. Possible reasons for the decrease in rates during 2011–2012 could include changes in transmission patterns, a recent change in surveillance case definition, increased uptake of strategies to reduce waterborne transmission, or a combination of these factors. Transmission of giardiasis occurs throughout the United States, with more frequent diagnosis or reporting occurring in northern states. Geographical differences might suggest actual regional differences in giardiasis transmission or variation in surveillance capacity across states. Six states did not report giardiasis cases in 2011–2012, representing the largest number of nonreporting states since giardiasis became nationally notifiable in 2002. Giardiasis is reported more frequently in young children, which might reflect increased contact with contaminated water or ill persons, or a lack of immunity.

Public Health Action: Educational efforts to decrease exposure to unsafe drinking and recreational water and prevent person-to-person transmission have the potential to reduce giardiasis transmission. The continual decrease in jurisdictions opting to report giardiasis cases could negatively impact the ability to interpret national surveillance data; thus, further investigation is needed to identify barriers to and facilitators of giardiasis case reporting. Existing state and local public health infrastructure supported through CDC (e.g., Epidemiology and Laboratory Capacity grants and CDC-sponsored Council of State and Territorial Epidemiologists Applied Epidemiology Fellows) could provide resources to enhance understanding of giardiasis epidemiology.

It’s not just bacteria and viruses; parasites in leafy greens

On July 7, 1997, a company physician reported to the Alexandria Department of Health (ADOH) that most of the employees who attended a corporate luncheon on June 26 at the company’s branch in Fairfax, Virginia, had developed gastrointestinal illness. On July 11, the health department was notified that a stool specimen from one of the employees who attended the luncheon was positive for Cyclospora oocysts. Many others tested positive. It was subsequently revealed in a July 19, 1997, Washington Post story citing pesto_basil_cyclosporalocal health department officials that basil and pesto from four Sutton Place Gourmet stores around Washington D.C. was the source of cyclospora for 126 people who attended at least 19 separate events where Sutton Place basil products were served, from small dinner parties and baby showers to corporate gatherings. Of the 126, 30 members of the National Symphony Orchestra became sick after they ate box lunches provided by Sutton Place at Wolf Trap Farm Park.

In May 2001, 17 people in British Columbia were sickened with cyclospora associated with basil from Thailand. In 2005, 300 people in Florida were sickened with cyclospora from fresh basil.

My aunt was part of that outbreak.

Parasites. They’re everywhere.

Canadian researchers report in the Journal of Food Protection a “relatively high prevalence” of Cyclospora, Cryptosporidium and Giardia in ready-to-eat packaged leafy greens; most of the products were grown in the U.S.

Abstract below.

Detection of Cyclospora, Cryptosporidium, and Giardia in ready-to-eat packaged leafy greens in Ontario, Canada

Journal of Food Protection®, Number 2, February 2013, pp. 192-369 , pp. 307-313(7)

Dixon, Brent; Parrington, Lorna; Cook, Angela; Pollari, Frank; Farber, Jeffrey

http://www.ingentaconnect.com/content/iafp/jfp/2013/00000076/00000002/art00016

Numerous foodborne outbreaks of diarrheal illness associated with the consumption of produce contaminated with protozoan parasites have been reported in North America in recent years. The present study reports on the presence of Cyclospora, Cryptosporidium, and Giardia in precut salads and lettuceleafy greens purchased at retail in Ontario, Canada. A total of 544 retail samples were collected between April 2009 and March 2010 and included a variety of salad blends and individual leafy greens. Most of these products were grown in the United States, with some from Canada and Mexico. Parasites were eluted and concentrated before detection by PCR and immunofluorescence microscopy. DNA sequences were aligned with reference sequences in GenBank. Cyclospora spp. were identified by PCR-restriction fragment length polymorphism in nine (1.7 % ) samples and by DNA sequence analysis. Cryptosporidium spp. were identified in 32 (5.9%) samples; 29 were sequenced and aligned with the zoonotic species Cryptosporidium parvum. Giardia duodenalis was identified in 10 (1.8%) samples, and of the 9 samples successfully sequenced, 7 aligned with G. duodenalis assemblage B and 2 with assemblage A, both of which are also zoonotic. The presence of Cryptosporidium oocysts and Giardia cysts was confirmed in some of the PCR-positive samples using microscopy, while Cyclospora -like oocysts were observed in most of the Cyclospora PCR-positive samples. The relatively high prevalence of these parasites in packaged salads and leafy greens establishes a baseline for further studies and suggests a need for additional research with respect to the possible sources of contamination of these foods, the determination of parasite viability and virulence, and means to reduce foodborne transmission to humans.