San Diego County Fair: Cluster Of 4 Pediatric E. coli STEC cases (1 Fatal)

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Every summer we look at rules for animal exhibits at state and county fairs to reduce the risk of transmitting avian or swine influenza (see Biosafety At The Fair This Summer), but novel flu isn't the only zoonotic risk posed by close contact with livestock.

Petting zoos are another popular attraction, and bacterial infections from Salmonella and E. coli are more common than you might think.

On Friday the San Diego County government released the following statement on 4 pediatric E. Coli STEC infections linked to the Sand Diego County Fair held in early June.   Tragically, one child has died.
 

Four Cases of E. coli Bacteria Linked to San Diego County Fair

By County News Center, County of San Diego Communications Office
Jun. 29, 2019 | 2:40 PM

The County of San Diego Health and Human Services Agency is reporting four confirmed or probable pediatric cases of Shiga-toxin-producing E. Coli (STEC) linked to contact with animals at the San Diego County Fair. One child has died.

HHSA Epidemiology Program and the County Department of Environmental Health are investigating the cluster of four infections. The ages of the four children range from 2 to 13 years of age. They visited the fair from June 8 to June 15 and had symptoms from June 10 to June 19.

Three of the four cases were not hospitalized. However, one of the four cases, a 2-year-old boy, was hospitalized and unfortunately died on June 24, from a complication of this disease.

The source of the E. Coli bacteria is under investigation, but all children had a report of visiting the animal areas or the petting zoo, or had other animal contact at the San Diego Fair. As a result, San Diego County Fair officials have closed public access to all animal areas, including the petting zoo.

“Our sympathies go out to the family of the child that died from this illness,” states Wilma J. Wooten, M.D., M.P.H., County public health officer. “While most people recover from this illness without complications, 5 to 10 percent of people diagnosed with STEC develop the life-threatening kidney infection.”

County Environmental Health also re-inspected food facilities that were visited by the children and found no link to the cases.

Most people with a STEC infection start feeling sick 3 to 4 days after eating or drinking something that contains the bacteria. However, illnesses can start anywhere from 1 to 10 days after exposure. Symptoms vary from person to person and often include:

• Severe abdominal cramps
• Watery or bloody diarrhea (3 or more loose stools in a 24 hour period)
• Vomiting
  

Symptoms may occur with or without a fever. When present, the fever usually is not very high (less than 101˚F/38.5˚C). Most people get better within 5 to 7 days. Some infections are very mild, but others are severe or even life-threatening. The public is asked to contact your health care provider if you have experienced these symptoms on or after June 8, and especially if you have diarrhea that lasts for more than 3 days or diarrhea that is accompanied by a fever higher than 102˚F, or blood in the stool, or so much vomiting that you cannot keep liquids down and you pass very little urine.

The most important step people should take to help prevent an STEC infection is to practice good handwashing hygiene. Always wash your hands thoroughly after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard). Everyone, especially young children, older individuals, and people with weakened immune systems, should wash their hands before eating or drinking.

We've seen some very large, and deadly, E. coli STEC outbreaks in the past, in including a 2011 EU outbreak linked to sprout seeds, that sickened more than 4,200 people and killed at least 50 (see ECDC: Lessons Learned On EHEC Outbreak).

Most outbreaks are much smaller, however, and are often linked to the consumption of contaminated food products (see CDC E. coli Outbreaks Page). 

The CDC explains the risks on their E. coli and Food Safety webpage:

Most E. coli are harmless and are part of a healthy intestinal tract. However, some cause diarrhea, urinary tract infections, respiratory illness, bloodstream infections, and other illnesses. The types of E. coli that can cause illness are spread through contaminated food or water and through contact with animals or people.

Two types of E. coli that cause diarrheal illness diagnosed in the United States are Shiga toxin-producing E. coli (STEC) and enterotoxigenic E. coli (ETEC).

STEC are a group of E. coli that produce Shiga toxin. This toxin causes people to have diarrhea, which can be bloody. When you hear reports about outbreaks of E. coli infections in the United States, they’re usually talking about a type called STEC O157.

ETEC are the leading cause of traveler’s diarrhea and a major cause of diarrhea around the world, especially among children.

A Dangerous Complication

About 5–10% of people diagnosed with STEC O157 infection develop a life-threatening complication known as hemolytic uremic syndrome (HUS)external icon, a type of kidney failure. Signs that a person is developing HUS include:

• urinating less often
• feeling very tired
• losing pink color in cheeks and inside the lower eyelids
  

People with HUS should be hospitalized because their kidneys may stop working and they may develop other serious problems. Most people with HUS recover within a few weeks, but some suffer permanent health problems or die.

Who is more likely to get an E. coli infection?

Anyone can get sick from harmful E. coli, but some people have an increased chance of infection. These people are:

• Children younger than 5 years of age
• Adults aged 65 and older
• People with weakened immune systems, including pregnant women
• People who travel to certain countries

 According to the CDC, animals most likely to carry E. coli O157 include:

• cows, especially calves
• goats
• sheep
• deer.

The benefits of having pets far outweigh the risks (see CDCs Healthy Pets, Healthy People webpage), but the CDC does recommend choosing pets wisely:

• Households with children 5 years of age and younger should not have pet reptiles (turtles, lizards, snakes), amphibians (frogs, toads), or backyard poultry because of the risk of serious illness from harmful germs spread between these animals and young children.
• People with weakened immune systems should take extra precautions when choosing and handling pets. Talk to your veterinarian for help picking the best pet.
• Pregnant women should avoid adopting a new cat or handling stray cats, especially kittens. Cats can carry a parasite that causes toxoplasmosis—a disease that can cause birth defects. If you are pregnant, you do not need to give up your current cat, but you should avoid changing cat litter.
• Pregnant women should avoid contact with pet rodents to prevent exposure to lymphocytic choriomeningitis virus, which can cause birth defects. If you’re pregnant and have a pet rodent, avoid direct contact and have someone else clean its habitat.

While animals can often become infected by contact with humans (reverse zoonosis), over the years we've looked a long list of fascinating, and unusual, zoonotic infections acquired from household pets, including:

• Last year, in MMWR: A Little Bit Of Seoul (Virus),we looked at a review of the 2017 (and first) outbreak of the Seoul hantavirus in North America, among pet rats (and a number people exposed to them) in the upper Midwest.
• Also in 2018, we caught up with a small, but growing number of fatal encephalitis cases among owners of imported (from South America) Variegated Squirrels (see ECDC: RRA On New Cluster Of Borna Disease Virus 1 - Germany).
• In Toxoplasmosis: Some Intriguing Para-Cites, we looked at the risks of zoonotic transmission from cats to humans of his fascinating parasite 
• In Transmission Of Bovine TB From Felines To Humans – UK, we looked at a report on two rare human infections with M. bovis – both associated with an outbreak in cats – which likely became infected via contact (directly or indirectly) with badger setts (dens). 
• In How Parrot Fever Changed Public Health In America, I wrote about how Chlamydophila psittaci, or `Parrot Fever’, spread across the country in 1929, sparking fears of a new pandemic. 
• In That Duck May Look Clean, But . . . , I wrote about a 2012 CDC investigation into an outbreak of Salmonella Montevideo involving 66 persons across 20 states linked to the handling of live poultry (baby chicks or ducklings or both) sold via mail-order hatcheries and  agricultural feed stores.
• Similar warnings have gone out in the past regarding Human Salmonella Infections Linked to Small Turtles.  
• And every year the CDC receives reports of human infection with Typhus, carried by fleas, often brought in by pets Texas: DSHS Issues Murine Typhus Alert
• Perhaps most famously,15 years ago the United States experienced an multi-state  outbreak of Monkeypox - when an animal distributor imported hundreds of small animals from Ghana - which in turn infected prairie dogs that were subsequently sold to the public (see 2003 MMWR Multistate Outbreak of Monkeypox --- Illinois, Indiana, and Wisconsin, 2003). 

While I'm sure my cat would take umbrage if I treated her like a potential bio-hazard every time I petted her, good hand hygiene is an absolute must after coming in contact with livestock.