Explosive Diarrhea – Cyclospora Outbreak among 1600 people in US: Causes, Symptoms, Diagnosis, Treatments

Explosive Diarrhoea – Introduction

There is an ongoing multi-state cyclospora outbreak happening in US. As of July 17, there are around 1650 cases reported across 34 states. CDC also investigating additional 5000 suspected cases which are yet to be lab confirmed. Some states, especially Michigan, have reported very high numbers, making 2026 one of the largest Cyclospora seasons in recent years. People suspecting that the outbreak is linked to fresh produces in several regions & It created an awareness among the people about what they are taking as food. 

Unlike the short lived bacteria causing diarrhoea which resolves in a day or two, cyclospora infection can lead to prolonged, explosive, watery diarrhoea with Abdominal cramp, nausea, vomiting, bloating, fatigue and all together causing dehydration with fluid loss. Proper treatment is necessary because the symptoms can persist more than 14 days if left untreated or mistreated with some different antibiotics.

This article explains everything you need to know about the current outbreak, including how the parasite spread, signs, symptoms, diagnosis, differential diagnosis with other microbes causing same kind of diarrhoea, and how its being treated. Whether you are having the symptoms or simply want to stay well informed, understanding cyclospora is an important part of protecting yourself and your family members.

What Is Cyclospora?

Cyclospora is a non motile microscopic coccideal parasite. There are two more same kind of parasites-

1. Cryptosporidium
2. Cystoisospora (Previously called isospora)

All these three are lesser widespread- mainly found in some parts of Europe and US.

Human are the only host, mainly infecting the small intestine. In human it causes cyclosporidiasis. But it is also reserved in many animals like Cow, Cat etc. Human to human transmission is very rare as the freshly passed stool with oocytes are not immediately infectious. But once ingested through contaminated food or water, the parasite infect the mucosa of small intestine causing disruptions in absorption of water and essential nutrients, causing profuse watery diarrhoea with abdominal pain.

Unlike other gastroenteritis, cyclospora can last several with without proper treatment. The symptoms can improve and then recurrence may happen which is frustrating for the patients

Why Cyclospora Outbreak / Explosive Diarrhoea in News?

Cyclospora has become a major public health concern in the United States following a sharp increase in the reported case of cyclosporiasis. Health officials have identified infections across numerous states, making it one of the largest cyclospora outbreak record in the country. As the case number continue to rise The centre for the Disease control and prevention (CDC) and The Food and the Drug Administration (FDA) working hard together to identify the source of the outbreak and prevent the additional illness.

Current investigations suggest that contaminated fresh produces, particularly shredded iceberg lettuce served as certain Taco Bell locations in five states, linked to the part of the outbreak. However the investigators are continuing to trace the food supply chain. Till now more than 30 states have reported cases, highlighting the widespread nature of outbreak

How does infection Spread?

• A person with cyclospora passes the unsporulated oocytes in their stool. This oocytes are not infectious immediately.
• They need 1-2 weeks (depending on the temperature and humidity) outside the body to become sporulated or infectious.
• This is why direct contamination from one person to another is highly uncommon.
• People become infected by consuming the CONTAMINATED fresh produces, waters with human faces
• After swallowing the infected oocytes, they release the parasite in small intestine.
• Outbreaks become quite common if the contaminated water is used on fresh produces, raw fruits and vegetables. So one contaminated farm can spread this disease across the country.

Incubation Period

Typical incubation period– around 7 days

Range– 3 to 14 days, although most of the people develop symptoms within 7 to 10 days.

Symptoms 

1. Profuse watery diarrhoea 💩 (most common symptom)
2. Explosive bowel movement 🚽
3.  Nausea & Vomiting 🤢
4.  Abdominal pain and bloating  😖
5. Excessive gas (flatulence) 💨
6.  Fatigue and Weakness 🥵
7.  Loss of appetite 🍽️
8.  Weight loss ⚖️
9.  Low grade fever 🤒 (Not always found)
10. Malaise 😩

Why diarrhoea is so severe?

• After contaminated food or water intake, cyclospora cayetanensis infects the epithelium cells of small intestine.

• These parasite causes blunting of the villi causing shortening of it., inflammation of the intestinal mucosa.

• These all greatly reduce the absorptive ability of intestine to absorb water, electrolytes, and nutrients.

• Because of the damage of intestine, it can not absorb water properly, so water remains in the lumen. Further unabsorbed nutrients even attract more water into the lumen.

• Inflammation increase the gut motility, so the internal lumen gets even lesser time to absorb the water.

• Inflammation of intestine also stimulate the secretion of chloride ions through chloride channels into lumen. Sodium also follows the chloride. Both (Na-cl) together attracts water inside the lumen.

• These all result in a large volume watery diarrhoea 

• So the combination of–

1. Poor Absorption 
2. Increased secretion 
3. Fast intestinal motility can lead to explosive, frequent, watery diarrhoea with other symptoms mentioned above.

Who is at higher risk?

• Immunocompromised people– Due to dysfunction or deficient CD4+T cell
• Elderly-Due to less effective CD4+T cell
• Children– Due to immature CD4+T cell
• Travellers– Due to contaminated food intake

Diagnosis 

• Stool examination
• Stool PCR
• Modified Acid fast stain
• UV fluorescence

Differential Diagnosis

Microbes	Difference
Entamoeba histolytica	Blood & Mucous mixed stool. A/W liver abscess. Pain in Right iliac fossa
Giardia	Greasy foul smelling stool. A/W malabsorption & Vit-A deficiency. Pain in Left iliac fossa
Cryptosporidium	Highly A/W HIV patients
Clostridium defficile	History of Recent Clindamycin or 2°/3°cephasporin (antibiotic) intake
Noro virus	Short duration (1-3 days)
Salmonella	A/W high fever, bloody diarrhoea
Shigella	Bloody diarrhoea with frequent urge to go bathroom
E. Coli (ETEC)	Large volume Watery diarrhoea
Vibrio cholerae	Rice water stool, effortless vomiting
Campylobactor	Bloody diarrhoea, abdominal pain in right iliac fossa (Resemble appendicitis)

Treatment

1. Maintain hydration

2. Maintain electrolytes 

3. Cotrimoxazole (Drug of Choice)

4. Alternative- Nitazoxanide

5. Avoid unnecessary antibiotics 

Visit CDC for more Information https://www.cdc.gov/cyclosporiasis/hcp/clinical-care/index.html

Prevention from Cyclospora Outbreak

• Wash hand with soap and water before eating or preparing food and after using the toilet

• Wash fresh fruit and vegetables throughly

• Avoid raw produces from the area with low sanitation

• Peel fruit if possible

• Use treated or boiled water for effected areas

• Proper disposal of human stool

• Travellers travelling to the endemic region should avoid untreated water and uncooked vegetable or salad.

FREQUENTLY ASKED QUESTIONS (FAQ)

•  Is cyclospora contagious?

• No. Cyclospora generally is not contagious from person to person. Most people get contaminated by fresh produces or contaminated water

• Can i get it from another person?

• No

• How long does the diarrhoea last?

• If untreated it may last for 6-7 weeks or even longer. But if treated with Cotrimoxazole it starts to improve within 2-3 days.

• Can cyclospora come back?

• Yes. Cyclospora causes relapsing diarrhea. So it may come back.The cycle may vary from days to weeks to months.

• Is it life threatening?

•  Usually not. Diarrhea can lean to dehydration, electrolytes imbalance, weight reduction Which may require hospitalisation, but death is very much uncommon in healthy individuals. It may rarely happen in immunocompromised patients.

• Which foods are mostly being contaminated?

• The infection spreads mostly from consuming raw food or fruits. Anything can get contaminated. prevention is more important

• Does cooking kill cyclospora?
• Yes. Cooking completely destroy the cyclospora. Its mainly the problem of consuming raw or uncooked food

• Can probiotics help?

• There is no evidence that probiotics help in cyclospora prevention. Probiotics mainly help to restore the gut microflora, not trying to kill any parasite.

Key Takeaways for Explosive Diarrhoea

• Cyclospora is a parasite that causes prolonged watery diarrhoea, ofter lasting few weeks to months if untreated

• Most infection comes from eating contaminated food and drinking contaminated water

• Symptoms usually begins after 1 week of exposure.

• The main symptom is Frequent watery diarrhoea accompanied by abdominal pain, bloating, fatigue, nausea, loss of weight

• The infection is very easily treatable with cotrimoxazole (TMP-SMX) for most of the patients

• Good hygiene alone cannot prevent the infection as food and water can also cause this disease.

• Proper cooking kills cyclospora. So throughly cooked food is highly suggestive 

• Immunocompromised individuals, children, elderly people are prone to the infection. Proper preventive measures should be taken for them.

• Seek medical attention if diarrhoea last more than few days.

• During the outbreak, follow the public health advisories and avoid recalled food products