Vector borne diseases: Awareness and Cure

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Search 23rd July, 2019 Public Speak here: http://www.newsonair.com/Main_Audio_Bulletins_Search.aspx

TOPIC: General studies 2 and 3

• Public Health issues
• Science and technology: medical research

In News: With the monsoon setting in after delay of a fortnight from the expected date, there has been a spurt in vector-borne diseases such as malaria, dengue, and chikungunya, which could be life-threatening in some cases and entails huge expenses for treatment.

Vector borne diseases (VBDs) form a major part of the communicable diseases in India. Ignorance and impoverished conditions of people contribute in creating source and spread of vector borne diseases and hinder disease control strategy. Slums are more vulnerable to vector borne diseases because of poor environmental condition, standard of living, poverty and ignorance of the people.

What are Vectors: Living organisms that can transmit infectious diseases between humans or from animals to humans (ticks, flies, sandflies, fleas, triatomine bugs and some freshwater aquatic snails)

• India is endemic for six major vector-borne diseases (VBD) namely malaria, dengue, chikungunya, filariasis, Japanese encephalitis and visceral leishmaniasis.
• India ranks very high in the list of countries with a serious malaria burden. In 2018, 3,99,134 cases of malaria and 85 deaths due to the disease were reported in the country, according to data from the National Vector Borne Disease Control Programme.
• Six states — Odisha (40%), Chhattisgarh (20%), Jharkhand (20%), Meghalaya, Arunachal Pradesh, and Mizoram (5-7%) — bear the brunt of malaria in India. These states, along with the tribal areas of Maharashtra and Madhya Pradesh, account for 90% of India’s malaria burden.

Methods for controlling mosquito breeding

• Release of larvivorous fish — such as gambusia fish which feed on larvae — into water bodies
• Indoor residual spraying (IRS)
• Use of insecticide treated bed nets
• Ensuring that water does not stagnate anywhere

Disease management

• Detecting the diseases in early stages and providing treatment
• Strengthening referral services
• Preparedness for the epidemic

Case Study: Odisha

From 4,36,850 malaria cases reported in 2015, Odisha had 66,301 cases reported in 2018, an 85-per cent reduction, giving the eastern coastal state the honour of reporting the highest reduction in malaria cases across the country, according to data from the Health Ministry’s National Vector Borne Disease Control Programme.

Surveying the period between March 2015 and March 2019, this year’s Economic Survey also stated that “malaria cases improved significantly…after implementation of Swachh Bharat Mission (SBM)” – Odisha brought about the highest reduction in malaria cases among children below five years but also notes that “major focus of SBM has been on making villages Open Defecation Free (ODF)”.

How it was achieved

1. The state government relies on a three-step project to keep malaria in check, executed by 47,147 ASHAs trained in diagnosing and monitoring malaria treatment. In the Early Detection and Complete Treatment (EDCT), an ASHA tests any fever case for malaria — so that treatment begins early and the parasite is killed before mosquitoes spread it.
2. Odisha also runs a programme called DAMAN — Duragama Anchala Re Malaria Nirakaran (or controlling malaria in remote locations) — as part of which mass screenings are organised twice a year at ‘malaria camps’ in these areas: in April-June, and September-October. Under DAMAN, the entire population of these areas undergoes a malaria test, irrespective of whether one has fever or malaria symptoms. Indoor residual spray method is used, in which a residual insecticide is applied to inner walls and ceilings of houses so that malaria vectors come in contact with the insecticide.
3. Third, the state government has distributed nearly 1.1 crore long-lasting insecticide nets (LLINs) to combat malaria exposure during sleep. ASHA workers go door-to-door to explain nuances of the net’s use.

Flip side of success: While successful test helps an ASHA get Rs 75, just testing, and achieving a negative result, fetches her only Rs 15 per case. As negative cases rise, malaria supervisors in Odisha worry whether the lower pay will demotivate ASHAs to work with equal fervour — or, worse, whether false cases will be reported to game the payment structure. Nine ASHAs in different low-endemic districts admitted that as negative tests keep increasing, the associated lower payment is a disincentive for them to continue testing each case of fever for potential malaria.

The new malaria vaccine

The vaccine (in Malawi) has taken three decades to come to fruition, and is the first one ever against a disease that kills 4,35,000 people a year, most of them children. India ranks high in the list of countries worst affected by the mosquito-borne disease.

The vaccine has been developed by GSK — the company is donating about 10 million doses of the product for the pilot. It was created in 1987 by GSK, and was subsequently developed with support from the Bill and Melinda Gates Foundation. In 2014, the vaccine cleared phase III clinical trials which certified that it was both effective and safe for use in humans. According to a description from PATH’s Malaria Vaccine Initiative (MVI), “RTS,S aims to trigger the immune system to defend against the first stages of malaria when the Plasmodium falciparum parasite enters the human host’s bloodstream through a mosquito bite and infects liver cells. The vaccine is designed to prevent the parasite from infecting the liver, where it can mature, multiply, re-enter the bloodstream, and infect red blood cells, which can lead to disease symptoms”.

PATH is an international nonprofit team of innovators which advises and partners with public institutions, businesses, grassroots groups, and investors to tackle the world’s toughest global health problems, including malaria. MVI works with various stakeholders towards the development of a malaria vaccine.

In Phase 3 trials conducted in Africa between 2009 and 2014, children received four doses of RTS,S. The vaccine prevented four in 10 cases of clinical malaria; three in 10 cases of severe malaria; and six in 10 cases of severe malaria anaemia, the most common reason children die from malaria. There were reductions in overall hospital admissions and the need for blood transfusions.

The Way Forward

Synergy: In high-burden regions, there is a need for Government’s ASHA or community health workers, who are equipped with rapid diagnostic kits, to quickly test and facilitate treatment. 

Negating drug resistance: The above is important to ensure that medicines are given only to those who need it. Resistance to a drug develops when people are treated randomly or when those taking the drug do not complete its full course.

Tackling under-reporting: data about people being treated in private hospitals may not be getting captured. If the Government mandated that the private sector report its malaria cases to them (as is with TB), that would be “powerful”.

Proactive surveillance system: There is a need to keep looking as to where the first cases emerge from and report them immediately. All clinics and hospitals, both government and private, should be able to inform the authorities immediately, when there are suspected cases of dengue or chikungunya.

Rapid response emergency vector control: With a focus on eradicating breeding places, prompt action should be taken to spray and fog suspected breeding grounds.

An awareness campaign to ensure that patients seek early hospitalization during an epidemic: When dengue and chikungunya cases start appearing, people need to be aware of what they should do at the first signs, such as seeking treatment from proper hospitals with facilities for blood tests.

Health personnel training: Health personnel should be given continuous training in the management and monitoring of dengue patients.

There is a greater need to tailoring strategies not just State by State but in some cases district by district to end the disease. It is also high time that a collective demand for timely provision of amenities is made at the community level and a sense of shared responsibility by the citizenry to ensure that the gains from government’s efforts to reduce the incidence of vector-borne diseases bear fruit.

Note:

Why is malaria such a major global public health challenge?

• Malaria is a potentially life-threatening parasitic disease caused by the parasites Plasmodium viviax (P.vivax), Plasmodium falciparum (P.falciparum), Plasmodium malariae (P.malariae), and Plasmodium ovale (P.ovale), transmitted by the female Anopheles mosquito.
• Malaria, according to the WHO, remains one of the world’s leading killers, claiming the life of one child every two minutes. Most of these deaths are in Africa, where more than 2,50,000 children die from the disease every year. Children under the age of 5 are at greatest risk from its life-threatening complications.

Rift Valley fever: Rift Valley fever (RVF) is an acute, fever-causing viral disease most commonly observed in domesticated animals (such as cattle, buffalo, sheep, goats, and camels), with the ability to infect and cause illness in humans.

‘MERA India’ to eliminate malaria by 2030: By The Indian Council of Medical Research – – a conglomeration of partners working on malaria control – in order to prioritise, plan and scale up research to eliminate the disease from India by 2030.

• It aims to harness and reinforce research in coordinated and combinatorial ways in order to achieve a tangible impact on malaria elimination.
• The National Vector Borne Diseases Control Program (NVBDCP) of India has developed a comprehensive framework to achieve the overarching vision of “Malaria free India by 2030”.

New paper-based test kit for Malaria Detection: A group of researchers from IIT Guwahati has developed a simple detection method that uses an instrument when in the lab or a piece of chromatographic paper when in the field.

Paper Test Kit for Malaria

• The kit can be used to detect Plasmodium parasite, which causes malaria and also specifically detect Plasmodium falciparum, a notorious species.
• Using an ordinary syringe fitted with a small magnet, magnetic beads and few chemicals inside, the researchers were able to specifically capture the antigen released by the parasites in the blood of malaria patients.
• As the blood has many interfering agents, the kit used magnetic bead–tethered aptamers (two small DNA molecules), which capture only the specific antigens and separate these from the blood serum to perform the reaction.
• This kit also has high stability in hot and humid conditions.

Working mechanism

• When the captured antigens interact with specific substrates inside the syringe, the blue dye turns pink. The dye is then adsorbed over a modified chromatographic paper.
• The formation of pink colour on the paper is a direct indication of the presence of parasites in the blood serum. The intensity of the colour increases when the concentration of antigen is high.
• The intensity of the colour change is measured using a spectrophotometer. This gives a quantitative measurement and can detect very low level of the antigen in blood.

Connecting the Dots:

1. Diseases like Dengue and Chikungunya claim many lives every year. The panic generated and the scale of response thereon give these diseases the essential characteristics of a disaster. Discuss. Also examine the areas that require immediate attention to address such medical disasters.
2. National Vector Borne Disease Control Programme (NVBDCP) is an umbrella programme for prevention and control of vector borne diseases. Vector borne diseases that are being targeted are:
3. Malaria
4. Dengue
5. Lymphatic Filariasis
6. Kala-azar

Which of the above options is/are correct?

1. 1, 2 and 3 only
2. 2, 3 and 4 only
3. 1, 3 and 4 only
4. All the above

Figure out: 

1. Is scrub typhus a vector borne disease?
2. Is it possible for a patient to have Dengue and Chikungunya together?
3. How does a patient suffer when he has Dengue?
4. Why do our bodies require platelets and blood plasma?
5. List of herbal remedies/plants useful to cure dengue?
6. What’s the %ge of GDP kept for funding on health initiatives?

Solution of qn 2: d. All of the above