Mosquito-borne diseases and how to prevent them

In the year 2020, 297 cases of dengue were reported in Delhi itself (till Sept. 20’). Dengue is one of the diseases spread by the bite of an infected mosquito. These types of diseases are called mosquito-borne diseases. The five most common diseases in this category that exists in India include dengue, malaria, Chikungunya virus and Zika virus. These diseases are responsible for millions of deaths around the world. In this article, we will look at some of the common mosquito-borne diseases in the country, their symptoms, treatments and preventive steps. 

Dengue 

Dengue is a viral infection caused by the bite of an infected mosquito. Over the past few years, the rising incidence of dengue cases and deaths has become alarming. It is transmitted by female mosquitoes.

Dengue can affect people differently. In some cases, the infection is so mild that the affected person may not even realise that they were sick. It can also cause severe flu-like symptoms in other cases. 

Severe manifestations of dengue can cause any number of complications such as severe bleeding, organ impairment and even death. 

Symptoms are expected to last from 2-7 days with an incubation period of 4-10 days (days for symptoms to appear after exposure to the virus). WHO has classified dengue as “Dengue” and “severe dengue” to help doctors develop the required treatment plan. 

Symptoms of dengue include

• High fever (greater than 104℉)
• Severe headache
• Pain behind the eyes
• Muscle and joint pains
• Nausea and/or vomiting
• Rash 
• Swollen glands

The patient may develop severe dengue 3-7 days after the onset of initial symptoms. This stage can be fatal as well. Warning signs of severe dengue include

• Severe abdominal pain 
• Persistent vomiting 
• Rapid breathing 
• Bleeding gums 
• Fatigue 
• Restlessness
• Vomiting blood 

If these symptoms manifest, care needs to be taken to avoid further complications. 

Malaria

Malaria is a disease caused by “plasmodium parasites” which is spread by the bite of the female anopheles mosquito. Over the years, several initiatives have been taken by both international and domestic institutions to curb the spread of malaria around the world. According to the world malaria report (December 2019), approximately 228 million cases of malaria were reported around the world in the year 2018. 

Climatic conditions and human immunity are two major factors which determine the spread of this disease. Symptoms of malaria include:

• High fever
• Chills
• Severe headache
• Nausea and vomiting
• Muscle pain 
• Fatigue 
• Sweating 
• Chest or abdominal pain 
• Cough 

Some patients also experience malaria “attacks”. A malaria attack starts with shivering and chills, which is followed by a high fever and sweating. The patient then returns to normal temperature, before the cycle starts again. 

Complications caused by malaria include:

• Cerebral malaria can result in brain damage, seizures and coma
• Breathing problems can occur if the patient develops pulmonary oedema (fluid filling in the lungs)
• Anaemia can develop as malaria damages the red blood cells 
• Low blood sugar or hypoglycemia can occur as a side effect of the medication used to treat malaria. 

Chikungunya 

Chikungunya is a virus that was first detected in 1952. The term “chikungunya” comes from a word in the Kimakonde language which translates to becoming contorted. It refers to the debilitating joint pain which causes the patient to have a stooped appearance. In the year 2020, 77 confirmed cases of chikungunya were reported in Delhi alone. Symptoms of chikungunya generally appear 3-7 days after the infected bite, they include:

• Fever
• Muscle and joint pain
• Headache
• Rash 
• Swelling in the joints

Chikungunya is not usually fatal. However, the symptoms can be extremely severe and disabling. 

Japanese encephalitis

Japanese encephalitis was diagnosed in India for the first time in 1955 (in Tamil Nadu). The most recent outbreak occurred in 2019, predominantly in regions of Bihar and Muzaffarpur. People of any age can contract this disease, however, it is more severe in children. Once infected, the individual is said to develop immunity from future infections. 

Symptoms can manifest 5-5 days after contracting the infection. They include:

• High fever
• Seizures
• Stiffness in the neck 
• Feeling confused or delirious
• Speech impairment
• Tremors
• Muscle weakness or paralysis

Zika virus

Zika virus is a mosquito-borne disease which is spread by the bite of an infected mosquito. One of the major risks of this disease is that it can be transmitted to the fetus in-utero, resulting in birth defects. The disease can also be transmitted through sexual intercourse.  

While there is currently no evidence of an ongoing zika virus outbreak in India, it is pertinent to note that there is a history of previous zika virus transmission in the country. Hence, it is important to be prepared for any possible outbreak. 

Symptoms of zika can last up to a week and fatalities associated with zika are rare. Most common symptoms of zika are:

• Fever
• Rash
• Headache
• Joint and muscle pain
• Red eyes

The most important aspect of preventing these diseases is limiting the breeding of mosquitos. The National Centre for Disease Control has set the following guidelines to protect oneself from mosquito-borne diseases:

Prevent/control mosquito breeding by:

• Covering all water tanks and containers with a tight lid
• Dispose and destroy unused containers, tyres, coconut shells or other waste products that can collect stagnant water
• Empty, clean, dry and change the water of desert coolers every week
• Use larvivorous fish (ex: guppies) in all open water bodies such as ornamental tanks, ponds etc. 
• Check for mosquito larvae and disinfect all containers holding water every week

The advisory also states guidelines for personal protection against mosquito bites. It recommends the use of mosquito nets, mosquito repellents and full-sleeved clothing to prevent bites. 

In most cases, outbreaks of mosquito-borne diseases are seasonal. Hence, prepare your home or locality before the expected outbreak by taking the aforementioned steps. Prevention of mosquito breeding is the best way to prevent any outbreak as there are no vaccinations for the same. 

If you experience any of the symptoms associated with the above diseases or if you require more information regarding these diseases, you can contact Dr Tushar Tayal at the CK Birla Hosptial-Gurgaon. 

Book an appointment with Internal Medicine specialist at the CK Birla Hospital, Gurgaon.