There is growing incidence of vector borne diseases across the country, affecting a large number of population. The Union Ministry for Health and Family Welfare has made all-out efforts for prevention and control of diseases such as dengue, malaria, chikungunya and swine flu
By Dr Manisha Yadav

The mosquito borne diseases are largely preventable through the various vector control strategies. The National Vector Borne Disease Control Programme covers various control strategies for six important vector borne diseases namely malaria, dengue, chikungunya, lymphatic filariasis, yellow fever and Japanese encephalitis. Let’s take a close look at the prevention and control of some of the most important of mosquito borne diseases that have assumed threatening proportions:

Swine Flu: The growing number of swine flu cases so early in the season has had doctors worried. There has been a spurt in swine flu cases reported across India. In Gujarat, the H1N1 virus has killed 242 people, next only to Maharashtra where official statistics compiled by the Union Health Ministry indicate that 400 people have died. The Kerala government said 420 people died and over 22 lakh persons were affected by various kinds of fever in the state since January.
Swine flu, the viral illness that became a pandemic in 2009, has made a comeback this year across the country with close to 12,500 cases being reported.
As many as 600 people have died of swine flu so far this year, a more than two-fold rise in such deaths compared to last year, the government informed the Rajya Sabha, recently.
Swine flu is a respiratory disease caused by influenza viruses that infect the respiratory tract of pigs and result in a barking cough, decreased appetite, nasal secretions, and listless behavior; the virus can be transmitted to humans. Symptoms of swine flu in humans are similar to most influenza infections: fever (100 F or greater), cough, nasal secretions, fatigue, and headache.

What is Swine Influenza?
Swine influenza (swine flu) is a respiratory disease of pigs caused by type A influenza virus that regularly causes outbreaks of influenza in pigs. Swine flu viruses do not usually infect humans, but rare human infections have occurred.
Swine flu viruses can cause high levels of illness in pig herds, but cause few deaths in pigs. Swine influenza viruses can circulate among swine throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans.

How many swine flu viruses are there?
Like influenza viruses in humans and other animals, swine flu viruses change constantly. Pigs can be infected by avian influenza and human influenza viruses as well as swine influenza viruses. When influenza viruses from different species infect pigs, the viruses can reassert (i.e. swap genes) and new viruses that are a mix of swine, human and/or avian influenza viruses can emerge. Over the years, different variations of swine flu viruses have emerged. At this time, there are three main subtypes that have been isolated in pigs: H1N1, H1N2, and H3N2.
Swine flu viruses are thought to spread among pigs mostly through close contact and possibly from contaminated objects moving between infected and uninfected pigs. Infected swine herds, including those vaccinated against swine flu, may have sporadic disease, or may show only mild or no symptoms of infection.

What are signs of swine flu in pigs?
Signs of swine flu in pigs can include fever, coughing (barking), discharge from the nose or eyes, sneezing, breathing difficulties, eye redness or inflammation, and going off feed. Some pigs infected with influenza, however, may show no signs of illness at all.

How common is swine flu among pigs?
H1N1 and H3N2 swine flu viruses are endemic among pig populations and something that the industry deals with routinely. Outbreaks among pigs normally occur in colder weather months (late fall and winter), but can occur year round. While H1N1 swine viruses have been known to circulate among pig populations since at least 1930, H3N2 influenza viruses did not begin circulating among pigs in the until about 1998. The H3N2 viruses initially were introduced into the pig population from humans. However, since then the H3N2 viruses circulating in pigs have changed. The H3N2 viruses circulating in pigs now are very different from the seasonal H3N2 viruses that circulate in humans.

Is there a vaccine for swine flu?
Just as there are influenza vaccines for people, there are specific swine influenza vaccines available for pigs.
Chikungunya: It is an illness caused by the transmission of chikungunya virus through the bites of the infected Aedes aegypti mosquitoes, which is also known as the Asian Tiger. These are the same mosquitoes that cause dengue fever as well. Some common symptoms of chikungunya are severe pain in the joints and fever. Other symptoms include fatigue, rashes, headaches and muscle pain. The chikungunya virus was found in 2013 for the first time. There are yet no vaccines or medicines to prevent the occurrence of this disease or an antiviral treatment to treat the chikungunya infection. However, this disease is generally not fatal and runs for a limited period of time only.
Chikungunya is a debilitating, non-fatal, viral illness that is spread by the bite of infected mosquitoes. It resembles dengue fever in presentation.
Humans are the major source or reservoir of chikungunya virus for mosquitoes. Therefore, the mosquito usually transmits the disease by biting an infected person and then biting someone else. An infected person cannot spread the infection directly to other persons i.e. it is not a contagious disease.

Vector of Chikungunya
Chikungunya is spread by the bite of Aedes mosquito, primarily Aedes aegypti.

Signs and Symptoms of Chikungunya
Chikungunya usually starts suddenly with fever, chills, headache, nausea, vomiting, joint pain, and rash. In Swahili, “chikungunya” means “that which contorts or bends up”. This refers to the contorted or stooped posture of patients who are afflicted with the severe joint pain (arthritis) which is the most common feature of the disease. In children, usually there are no symptoms of the disease.
In chikungunya, the patient usually recovers. However, convalescence can be prolonged and persistent joint pain may require analgesics and long-term anti-inflammatory therapy.

Following are some of the ways to prevent the spread of this disease
i.Clean out the standing water
Standing water is the main cause for the spread of this disease as it provides a perfect place for the chikungunya mosquito to breed. Even though this mosquito is an aggressive daytime biter, make no mistake for it’s greedy for human blood. Make sure to keep your surroundings neat and clean. Do not let the water be kept at a certain place for a long period of time so it becomes a breeding place for the chikungunya mosquito. Regularly clean your coolers and change its water, change the water of your flowerpots and clean any other place the water is stagnant at.
2. Keep your skin covered
If you are a traveler, the best thing you can do to protect yourself is to cover your skin in order to prevent the mosquito bites. Remember to cover your limbs specifically. Wear clothes that cover maximum parts of your body. Another precaution that you can take is to wear a bug spray.
3. Clean your surroundings
The best way to minimise the risk of chikungunya is to keep your surroundings clean. Stay in a properly air-conditioned place, do not litter around the place and stay away from the places that you think might be a reservoir of any kind of mosquitos. Pregnant women, children and older people are mostly the infected ones. So, help them and keep their surroundings clean and tidy as well.
4. Reduce the risk of mosquito bites
As we have already discussed, chikungunya spreads through mosquito bites. Hence, preventing mosquito bites is the best way to prevent chikungunya. It is recommended to use mosquito repellents to prevent mosquito bites. One should wear mosquito repellents at all times, regardless of being indoors or outdoors. But keep in mind that mosquito repellents don’t kill them.
If one is infected with the chikungunya virus, there is no particular treatment for it, other than taking proper rest, diet and medications. You need to survive through the disease. For ladies who are pregnant, it is really difficult to manage tasks by themselves so a family member should be around to help them.
Moreover, the doctors should have clean hands and tools while performing any kind of treatment. For the kids, it should be ensure that they don’t play in the swampy and dirty water or any unhygienic area in general. And for those who are old, they should take care of themselves as well as their surroundings.
There are several ways you can save yourself from getting bitten, also do remember to apply the anti-repellent creams behind your ears and around your ankles and toes. Mosquitos can attack at any places, you need to keep safe.
Another good tip is to spray the aerosol in all the covers of your environment, may it be your school, office or home as well as under all openings you can find.These tips will keep you safe and minimise the risk of chikungunya.

Treatment of Chikungunya
There is no specific treatment for chikungunya. Supportive therapy that helps ease symptoms involves administration of medicines like the paracetamol and taking plenty of rest. Infected persons should be isolated from mosquitoes in order to avoid transmission of infection to other people.
The government has put Oseltamivir, marketed as Tamiflu, in schedule H1 to enable it to be sold by all licensed chemists under prescription. The drug was earlier in schedule X, wherein only certain selected pharmacists were authorised to stock it.

MALARIA
Malaria is a potentially life threatening parasitic disease caused by parasites known as Plasmodium viviax (P.vivax), Plasmodium falciparum (P.falciparum), Plasmodium malariae (P.malariae) and Plasmodium ovale (P.ovale). Recently, a fifth parasite Plasmodium knowlesi (P. knowlesi) has been found to be existing in India. However, two types of parasites, Plasmodium vivax, P. falciparum, are commonly reported from India. Infection with P.falciparum is the most deadly form of malaria.
Malaria is transmitted by the bite of infective Anopheles mosquito. Man develops disease after 10 to 14 days of being bitten by an infective mosquito. Inside the human host, the parasite undergoes a series of changes as part of its complex lifecycle in liver cells (pre-erythrocytic schizogony) and red blood cells (erythrocytic schizogony).

Symptoms of malaria
The symptoms of malaria typically include fever, headache, vomiting and other flu-like symptoms. As the parasite infects and destroys red blood cells, this results in easy fatigability due to anaemia, fits/convulsions and loss of consciousness. In case of cerebral malaria, the malarial parasites are carried by blood to the brain and other vital organs. Malaria in pregnancy poses a substantial risk to the mother, foetus as well as the newborn infant.

Vectors of Malaria
There are many vectors of malaria but the main vector of malaria is Anopheles culicifacies. The vector of malaria can be identified by the presence of spotted wings and resting position at an angle except Anopheles culicifacies.

Habits of the Anopheles Mosquito

Feeding habits: Anopheles culicifacies is a zoophilic species (affinity towards animals) and when high densities build up, then they feed on man.
Resting habits: The vector rests during daytime in human dwellings and cattle sheds.
Breeding places: It breeds in rainwater pools and puddles, borrow pits, river bed pools, irrigation channels, seepages, rice fields, wells, pond margins, sluggish streams with sandy margins. Extensive breeding of the mosquito is generally encountered following monsoon rains.
Biting time: Biting time of each vector species is determined by its generic character, but can be readily influenced by environmental conditions. Most of the vectors, including Anopheles culicifacies, start biting soon after dusk. Therefore, biting starts much earlier in winter than in summer but peak time varies from species to species.

Treatment of Malaria
Chloroquine is the drug of choice for uncomplicated malaria. Drug Distribution Centres (DDCs) and Fever Treatment Depots (FTDs) have been established in the rural areas for providing easy access of anti-malarial drugs to the community.
Alternative drugs that are recommended as per the drug policy of malaria and to be used in chloroquine resistant cases include Artesunate, Artemether and Arteether.

DENGUE
Dengue is a viral disease which is transmitted by the infective bite of Aedes aegypti mosquito also known as tiger mosquito. Man develops disease after 5-6 days of being bitten by an infective mosquito.

It occurs in two forms: Dengue Fever and Dengue Haemorrhagic Fever (DHF). Dengue fever is a severe, flu-like illness. Dengue Haemorrhagic Fever (DHF) is a more severe form of disease, which may cause death due to bleeding leading to low blood pressure and low blood volume. Person suspected of having dengue fever or DHF must visit a doctor immediately.

Signs and Symptoms of Dengue
The signs and symptoms of Dengue includes abrupt onset of high fever, severe frontal headache, pain behind the eyes which worsens with eye movement, muscle and joint pains, loss of sense of taste and appetite, measles-like rash (due to low platelet count) over chest and upper limbs and nausea and vomiting.

Vector of Dengue
The vector of dengue is Aedes aegypti mosquito. It is a small, black mosquito with white stripes and is approximately 5 mm in size. It takes about 7 to 8 days to develop the virus in its body and transmit the disease.
Habits of the Aedes Mosquito
a) Feeding Habit: Aedes mosquito is a day biter and mainly feeds on human beings in domestic and peri-domestic situations. It bites repeatedly.
b) Resting Habit: Aedes mosquito rests in the domestic and peridomestic situations especially in the dark corners of the houses, on hanging objects like clothes, umbrella, etc. or under the furniture.
c) Breeding Habits: Aedes aegypti mosquito breeds in any type of manmade containers or storage containers having even a small quantity of water. The eggs of Aedes aegypti can live without water for more than one year. The favoured breeding places of the mosquito are desert coolers, drums, jars, pots, buckets, flower vases, plant saucers, tanks, cisterns, bottles, tins, tyres, roof gutters, refrigerator drip pans, cement blocks, cemetery urns, bamboo stumps, coconut shells, tree holes and places where rainwater collects or is stored.

Treatment of Dengue
Intake of plenty of oral fluids and rest is advised for the patient. Symptomatic treatment is given in form of antipyretics and anti-inflammatory drugs (such as paracetamol). However, it is advisable that self-medication should not be done and one should always consult the doctor immediately.
Vector Control Strategies
The vector control strategies are largely the same for the mosquito borne diseases. The various control strategies for mosquitoes include environmental control, chemical control, biological control, personal protective prophylaxis and community participation. Early case Detection and Prompt Treatment (EDPT): EDPT is the main strategy necessary for all the cases of mosquito borne diseases to prevent their transmission.
Chemical Control: Use of Indoor Residual Spray (IRS) with insecticides is recommended under the National Vector Borne Disease Control Programme (NVBDCP).

NADDA DECLARES WAR ON vector borne diseases

J P Nadda, Union Minister for Health and Family Welfare held a high level meeting to review the activities for prevention and control of vector borne diseases in Delhi, recently.
Satyendra Jain, Health Minister, Government of Delhi, Mayors of Delhi, C K Mishra, Union Health Secretary, Dr Soumya Swaminathan, Secretary, Department of Health Research (DHR), Dr Jagdish Prasad, DGHS, Medical Supdts of the Central Government hospitals in Delhi, senior officials from Union Health Ministry,Government of Delhi, ICMR, NCDC and NVBDCP were also present during the meeting.
Nadda stressed on the critical importance of prevention of vector-borne diseases and stated that all stakeholders including the Government of Delhi, Municipal Corporations, RWAs, NGOs and the people have an important role to play in the prevention of breeding of the vectors that cause these diseases. He stated that a strong awareness campaign is very effective for educating people to keep their home and surrounding areas free of water logging.
He urged the Health Minister of Delhi to launch a house-to-house IEC campaign for creating widespread awareness. The Mayors of Delhi informed that such a campaign has already started and various forms of media are being used to reach out to people. Nadda stated that when people are equipped with proper information, they are capable of preventing such diseases and also seeking timely medical intervention.
The Union Health Minister suggested for a workshop to be organised by the Delhi Government for all concerned agencies and stakeholders to sensitise them on the protocols for prevention and management of vector-borne diseases that normally see a spike during the monsoon season. He assured the support of the Union Health Ministry in all efforts of the State government to build their capacity. He added that master trainers that had received traininglast year and this year should be engaged to build the capacity of other health workers too.
Nadda highlighted the importance of maintaining adequate quantity of testing kits, drugs etc., at the government hospitals and chemists. He requested the Delhi Government to issue an advisory to all chemists to ensure adequate stock of necessary drugs. He also suggested for hospitals to ensure that adequate number of isolation wards are available and to ensure that protocols for ventilator management are followed.