CHOLERA

History

The word cholera is from Greek word ‘kholera’. The disease first spread by trade routes (land & sea) to Russia in 1817, then to Western Europe, & from Europe to North America.

In Russia alone, between 1847 & 1851, more than one million people perished of the disease. It killed 150,000 Americans during the second pandemic between 1900 & 1920, perhaps eight million people died of cholera in India.

John Snow, in 1854, was the first to identify the importance of contaminated water in its cause. Cholera is now no longer considered a pressing health threat in Europe & North America due to filtering & chlorination of water supplies, but still heavily affects populations in developing countries. Last two year many people die of cholera in western region of Nepal.

Introduction

Cholera is an acute intestinal infection caused by ingestion of food or water contaminated with the bacterium Vibro Cholerae. Most persons infected with V. cholera do not become ill, although the bacterium is present in their feces for 7-14 days. Less than 20% of ill person develop typical cholera with signs of moderate or severe dehydration.

Signs & symptoms

The primary symptoms of cholera are profuse painless diarrhea & vomiting of clear fluid. These symptoms usually start suddenly, one to five days after ingestion of the bacteria. The diarrhea is frequently described as “rice water” in nature & may have a fishy odor. An untreated person with cholera may produce 10-20 liters of diarrhea a day with fatal results. For every symptomatic person there are 3 to 100 people who get the infection but remain asymptomatic.

Transmission

Cholera is typically transmitted by either contaminated food or water. In the developed world, seafood is the usual cause, while in the developing world it is more often water. Cholera is rarely spread directly from person to person.

Epidemiology

It is estimated that choleras affects 3-5 million people worldwide, & causes 100,000-130,000 deaths a year as of 2010. This occurs mainly in the developing world. In the early 1980s, death rates are believed to have greater than 3 million a year. It is difficult to calculate exact numbers of cases, as many go unreported due to concerns that an outbreak may have negative impact on the tourism of a country. Cholera remains both epidemic & endemic in many areas of the world.

Treatment

Fluid- In most cases, cholera can be successfully treated with oral rehydration therapy (ORT), which is highly effective, safe, & simple to administer.

Electrolyte & Antibiotic (Doxycycline, cotrimoxazole, erythromycin, tetracycline, and chloramphenicol) can be used.

Prevention

Effective water sanitation practices, if instituted & adhered to in time, are usually sufficient to stop an epidemic. There are several ways along the cholera transmission path at which its spread may be halted. Example sewage treatment, sources decontaminate & water purification.

Subash Adhikari

Department of Microbiology