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History of epidemics in Nepal (Part II): 6 diseases that troubled Nepal in 21st century

Continued from Part I

With the onset of the new millennium, epidemics in Nepal saw a range of new diseases and their outbreaks. Some were highly communicable whereas many were non-communicable diseases. Some of the newer epidemics reported in Nepal are as follows:

1. TYPHOID

Photo: Medicinenet

Typhoid fever is a life-threatening infection that can lead to high fever, constipation or diarrhoea, nausea, abdominal pain, and vomiting. It is caused by the bacterium called Salmonella Typhi. The infection is spread through contaminated food and drinking water with the faeces of an infected person which enters into the gastrointestinal tract and begins to multiply showing different symptoms as mentioned earlier.

It was in 2002 when the typhoid fever first saw the outbreak in Nepal with over 6,000 cases recorded in Bharatpur in a span of seven weeks. After this, additional 112 cases of typhoid fever were reported in Dhulikhel Hospital the same year. Later in 2014, an outbreak of the disease was reported in Bajura district with over 50 daily cases.

The Nepal government has introduced two types of vaccines for the treatment of typhoid: the inactivated injectable vaccine (lasting two to three years), and the live attenuated oral vaccine (lasting five to seven years). Although these vaccines do not provide 100% protection, they will reduce the severity of the illness.

2. DENGUE

Dengue is a mosquito-borne single-stranded RNA virus infection that is caused by the four well-established serotypes of viruses (DENV 1-4) belonging to the Flaviviridae family. This disease emerges in the form of dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). The infection is transmitted through the bite of infected Aedes aegypti and Aedes albopictus or female mosquitoes that feed during the daytime. These mosquitoes are generally sourced around stagnant water bodies.

Dengue was reported in October 2004 for the first time in a Japanese traveller who had travelled to Nepal. In 2006, all the four serotypes of dengue virus were reported. But a major outbreak came only in 2016, where a total of 1,473 cases were reported from Chitwan, Jhapa, Rupandehi, and Makawanpur. Another large dengue outbreak was in 2019 with 14,442 cases from Kathmandu, Chitwan, Kaski, Rupandehi, and Makawanpur. Dengue also lacks a proper vaccine to date, but proper sanitation and vector control to curb breeding of mosquitoes are advised.

3. BIRD FLU

Photo: Wikimedia

Bird flu, also known as avian influenza, is an infectious disease caused by any of the influenza type A viruses that normally infect birds. Altogether, 16 different types of bird flu have been identified including H5N1, H7N9, and H1N1. This disease affects several types of birds, wild animals, and farmed poultry. This flu is spread to humans through saliva, nasal secretions, faeces, and feed of birds causing severe respiratory-related problems.

In January 2009, the bird flu (H5N1) virus outbreak was seen in the backyard of a poultry farm in a village of Jhapa. And, the first outbreak was confirmed in Kakarbhitta where 28,000 chickens in the area were killed to control the virus. Also, the first case of bird flu death in Nepal was on April 8, 2009, where a 21-year-old youth of Kavre died of bird flu. However, the highest number of outbreaks, 201 cases, was reported in the year 2013.

The best way to prevent bird flu is to avoid exposure to birds and their faeces whenever possible. For treatment, antiviral drugs such as oseltamivir (Tamiflu), and zanamivir (Relenza) are recommended for bird flu (type A).

4. HEPATITIS

Photo: News Medical

Hepatitis is inflammation of the liver tissues. It is caused by viruses such as hepatitis A, B, C, D, and E, whereas other causes include heavy alcohol use, certain medications, toxins, other infections, autoimmune diseases, and non-alcoholic steatohepatitis (NASH). Hepatitis A and E are spread by contaminated food and water. Hepatitis B is sexually transmitted; hepatitis C spreads through infected blood; and lastly, hepatitis D is spread to the patients of hepatitis B.

In April 2014, an outbreak of hepatitis E first started in Biratnagar with 11 cases who visited hospitals with acute jaundice. In the next seven weeks, additional 1,861 patients reached the hospital complaining of acute jaundice, where 123 patients were admitted to the hospitals. Between April-May in 2014, HEV infected more than 6,000 individuals with 11 deaths in Biratnagar.

This disease is mainly associated with faecal contamination of drinking water.

The Nepal government with the aid of GAVI has introduced phase-wise Hepatitis B vaccine programmes from 2002 to 2004. It is currently administered as a pentavalent vaccine along with Hemophilus influenza B (HIB) and Diphtheria Pertussis and Tetanus (DPT) vaccines at six, 10, and 14 weeks of age.

5. SCRUB TYPHUS

Photo: University of California

Scrub typhus is a mite-borne disease which is caused by ‘orientia tsutsugamushi’ which carries mites in their larval stage when they are chiggers that feed on forest and rural rodents including rats, voles, and field mice. The mites are both the vector and the natural reservoir for O.tsutsugamushi. Symptoms of this disease start suddenly after the incubation period of six to 21 days that include fever, chills, headache, and generalised lymphadenopathy.

Some reports claim the presence of scrub typhus in 1981, 2004, and 2007 in Nepal. However, the first outbreak of scrub typhus was officially reported only in 2015 when 101 cases were reported from 16 districts, with eight deaths. Again, in 2016, there was an outbreak where 18 deaths were reported with more than 800 cases in 47 districts.

As per now, there is no vaccine or preventive measures for scrub typhus in Nepal. However, doctors use antibiotic doxycycline to treat this disease. For fast recovery, these antibiotics are given soon after symptoms begin.

6. CHICKENPOX

Photo: Clinical Advisor

Chickenpox is a very contagious infection which is caused by the varicella-zoster virus. It causes an itchy rash with small, fluid-filled blisters. Blisters pop and start to leak over 10 to 21 days and after that, the crust and scab appear before healing which might take five to 10 days. Usually, chickenpox is milder, but in some cases, blisters can spread to the nose, mouth, eyes, and even genitals. Apart from children, chickenpox is highly contagious to people who have not had the disease or been vaccinated against it.

The first outbreak of chickenpox in Nepal was reported in 2015 in Baidauli VDC of Nawalparasi, where 55 cases from 27 households were affected by chickenpox. This outbreak continued for 45 days. The number of cases rapidly rose after the detection of the primary case. The chickenpox vaccine is called the varicella vaccine made from a live but weakened virus.

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