Balantidiasis

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Balantidiasis

Introduction

Disease History, Characteristics, and Transmission

Scope and Distribution

Treatment and Prevention

Impacts and Issues

BIBLIOGRAPHY

Introduction

Ingestion of the protozoan parasite Balantidium coli causes balantidiasis (ba-lan-ti-DYE-a-sis) infection. This parasite is transmitted from animal reservoirs to humans by oral contact with fecal matter. This transmission occurs when unwashed food or unclean water is ingested, or if hands are not washed after handling animals. While balantidiasis infection is rare, and most cases are asymptomatic, some cases result in diarrhea, dysentery, colitis, abdominal pain, weight loss, and fatalities. Treatment is effective and involves a short course of antibiotics, which eradicates the parasite.

Balantidiasis occurs worldwide, but is more common in areas in which humans live in close contact with live-stock, and particularly in areas with poor sanitation or other health problems. Infection is best prevented by treating water, washing food and hands, and reducing contact with livestock. Improving community sanitation standards, as well as educating communities on the importance of sanitation, can also help reduce infection.

WORDS TO KNOW

RESERVOIR: The animal or organism in which the virus or parasite normally resides.

TROPHOZOITE: The amoeboid, vegetative stage of the malaria protozoa.

Disease History, Characteristics, and Transmission

Balantidiasis is an intestinal infection caused by the parasite Balantidium coli. Humans are infected when they ingest B. coli cysts—immobile, protected forms of the parasite. Once in the body, these cysts break open and a mobile stage called a trophozoite is released. The trophozoite feeds on bacteria within the intestine, or enters the intestinal lining and secretes a tissue-destroying substance. As a result, sores (ulcers) and abscesses develop in the intestinal lining. New cysts are formed by the trophozoites and are excreted from the body in the feces. The cysts are well-protected and can remain outside the body under favorable conditions for many weeks.

B. coli are transmitted to humans from animal reservoirs such as livestock, rodents, and non-human primates. The most common reservoirs are pigs, which are often infected with B. coli, but tend to be asymptomatic. Transmission occurs when humans ingest food or water contaminated with the feces of infected animals, or when the mouth comes in contact with something contaminated with feces, such as unwashed hands.

Balantidiasis infection is uncommon in humans, and most cases are asymptomatic. However, asymptomatic humans are still capable of spreading the infection. When symptoms do appear, the most common symptoms are diarrhea, dysentery, abdominal cramps, and inflammation of the colon. In severe cases, perforation of the intestinal wall may occur, which can be fatal.

Scope and Distribution

Balantidiasis infection occurs worldwide, although it is more common in the tropics. It also is more common in regions where livestock, particularly pigs, is kept in conjunction with poor water systems and poor sanitation. Bolivia, the Philippines, and Papua New Guinea have all had outbreaks of balantidiasis, although the prevalence of the parasite B. coli is usually lower than 1%.

Treatment and Prevention

Medical treatment of balantidiasis is usually effective and is administered to both symptomatic and asymptomatic patients. Asymptomatic patients are treated in order to prevent them from spreading infection to others. Symptomatic patients are treated because untreated balantidiasis can become chronic and lead to dehydration, abdominal bleeding, and perforation of the intestinal wall, any of which—left untreated—can be fatal. Treatment usually involves oral administration of one of the following antibiotics: tetracycline, metronidazole, and iodoquinol. Tetracycline is the treatment of choice, but it is not recommended for pregnant women and children under the age of eight.

The most effective methods to prevent infection by B. coli involve improving sanitation. This includes boiling contaminated water prior to using it, washing hands after handling pigs or using the toilet, effectively washing and cooking food prior to eating, and preventing water sources from coming into contact with animal and human feces. As the most common mode of infection is from pigs to humans, reducing contact between pigs and humans will reduce infection. This can be achieved by preventing pigs from sharing human water sources, washing hands after handling pigs, and putting up barriers between pig and human living areas.

Impacts and Issues

Balantidiasis infection most commonly occurs in communities in which sanitation is poor. This situation often arises due to a lack of resources to provide adequate sanitation, as well as a lack of education about sanitary living. Infections by the parasite B. coli have also been found to cause more severe infection in people who are already debilitated. This may be due to malnourishment, coinciding parasitic infections, or a weakened immune system.

Efforts to improve sanitation and health in communities may lead to a reduction in the prevalence of infection. Installing hygienic measures such as potable water sources, toilets separate from living areas, and separate housing for livestock and humans will greatly reduce the likelihood of transmission of B. coli between animals and humans. In addition, educating people on the risks associated with poor hygiene may also help prevent transmission. Addressing other health issues within communities, such as coexisting parasitic infections and malnourishment, will help improve the overall health of the community and will aid in reducing the severity of any infections that do occur.