| Cyclosporiasis | |
|---|---|
| Other names | cyclosporosis |
 | |
| Cyclospora cayetanensis | |
| Specialty | Infectious disease |
Cyclosporiasis is a disease caused by infection withCyclospora cayetanensis, a pathogenicapicomplexanprotozoan transmitted byfeces or feces-contaminated food and water.[1]Outbreaks have been reported due to contaminated fruits and vegetables. It is not spread from person to person, but can be a hazard for travelers as a cause ofdiarrhea.
Cyclosporiasis primarily affects humans and otherprimates. When anoocyst ofCyclospora cayetanensis enters thesmall intestine, it invades themucosa, where it incubates for about one week. After incubation, the infected person begins to experience severe waterydiarrhea, bloating, fever, stomach cramps, and muscle aches.[citation needed]
The parasite particularly affects thejejunum of the small intestine. Of nine patients in Nepal who were diagnosed with cyclosporiasis, all had inflammation of thelamina propria along with an increase ofplasma in the lamina propria. Oocysts were also observed induodenal aspirates.[2]
Oocysts are often present in the environment as a result of using contaminated water or human feces asfertilizer.
Diagnosis can be difficult due to the lack of recognizable oocysts in the feces.PCR-basedDNA tests andacid-fast staining can help with identification.[citation needed]
There is novaccine to prevent cyclosporiasis in humans at present, but one is available for reduction of fetal losses in sheep.[citation needed]
The infection is often treated withtrimethoprim/sulfamethoxazole, also known as Bactrim or co-trimoxazole, because traditional anti-protozoal drugs are not sufficient. To prevent transmission, food should be cooked thoroughly and drinking water from streams should be avoided.
The first recorded cases of cyclosporiasis in humans were as recent as 1977, 1978, and 1979. They were reported by Ashford, a British parasitologist who discovered three cases while working inPapua New Guinea. Ashford found that the parasite had very latesporulation, from 8–11 days, making the illness difficult to diagnose. When examining feces, the unsporulated oocysts can easily be mistaken for fungal spores, and thus can be easily overlooked.[3]
In 2007, Indian researchers published a case report that found an association betweenCyclospora infection andBell's palsy. This was the first reported case of Bell's palsy following chronicCyclospora infection.[4] In addition to other extra-intestinal reports, cyclosporiasis might be involved in either reversible neuronal damage or other unknown mechanisms to lead toGuillain-Barré syndrome or Bell's palsy.
In 2010, a report ofCyclospora transmission via swimming in theKathmandu Valley was published in theJournal of Institute of Medicine.[5] The researchers found thatopenly defecated human stool samples around the swimmer's living quarters and near the swimming pool were positive forCyclospora. However, they did not find the parasite in dog stool, bird stool, cattle dung, vegetable samples, or water samples. They concluded that pool water contaminated via environmental pollution might have caused the infection, as the parasite can resist chlorination in water.[6]
Cyclosporiasis infections have been well reported in Nepal. In one study, Tirth Raj Ghimire, Purna Nath Mishra, and Jeevan Bahadur Sherchan collected samples of vegetables, sewage, and water from ponds, rivers, wells, and municipal taps in the Kathmandu Valley from 2002 to 2004.[7] They foundCyclospora in radish, cauliflower, cabbage, and mustard leaves, as well as sewage and river water. This first epidemiological study determined the seasonal character of cyclosporiasis outbreaks in Nepal during the rainy season, from May to September.[8]
At the beginning of the AIDS epidemic in the early 1980s, cyclosporiasis was identified as one of the most importantopportunistic infections among AIDS patients.[9]
In 2005, Ghimire and Mishra reported a case of cyclosporiasis in a patient with low hemoglobin and suggested that this coccidian might be involved in reducing hemoglobin due to lack of immune system.[10] In 2006, their groups published a paper about the role of cyclosporiasis in HIV/AIDS patients and non-HIV/AIDS patients in the Kathmandu Valley.[11]
In 2008, Indian researchers published a report about the epidemiology ofCyclospora in HIV/AIDS patients in Kathmandu.[12] They examined samples of soil, river water, sewage, chicken stool, dog stool, and stool in the streets, and found them positive forCyclospora. They also evaluated several risk factors for cyclosporiasis in AIDS patients.[12]
Although it was initially thought thatCyclospora was confined to tropical and subtropical regions, occurrences of cyclosporiasis are becoming more frequent in North America. According to theCenters for Disease Control and Prevention, there have been 11 documented cyclosporiasis outbreaks in the U.S. and Canada since the 1990s. The CDC also recorded 1,110 laboratory-confirmed sporadic instances of cyclosporiasis.[13]
Between June and August 2013, multiple independent outbreaks of the disease in the U.S. sickened at least 631 people across 25 states.[14][15] Investigations later identified a bagged salad mixture as the cause of an outbreak inIowa andNebraska.[16]
In 2015, the CDC was notified of 546 persons with confirmed cyclosporiasis infection across 31 states. Cluster investigations inTexas, where the greatest number of infections was reported, indicated that contaminatedcilantro was the culprit.[17]
During July 21–August 8, 2017, the Texas Department of State Health Services (DSHS) was notified of 20 cases of cyclosporiasis among persons who dined at a Mediterranean-style restaurant chain (chain A) in the Houston area.[18]
On July 31, 2018, the United States Department of Agriculture (USDA) issued a public health alert for certain beef, pork and poultry salad and wrap products potentially contaminated with Cyclospora.[19]The contamination came from the chopped romaine lettuce used in these products.
In June 2020, the CDC and other regulatory bodies began investigating an outbreak of Cyclosporiasis in the Midwestern United States linked to bagged salad mix.[20] On June 27, 2020, Fresh Express announced a voluntary recall of over 91 Fresh Express and private label salad products.[21]
