WORLD HEALTH DAY CELEBRATIONS. ESI HOSPITAL,RAMACHANDRA PURAM.

7, APRIL,2014. THEME:VECTOR BORNE DISEASES- SMALL BITE, BIG THREAT.(W.H.O)

C.M.E ON :

PREVENTION OF VECTOR BORNE DISEASES-MALARIA,DENGUE,etc.

BY DR P SUDHAKAR NAIK.

C.A.S.

ESI HOSPITAL,RAMACHANDRA PURAM.

MEDAK DIST.

World Health Day is celebrated on 7 April every year to mark the anniversary of the founding of WHO in 1948.

Each year a theme is selected that highlights a priority area of public health.

The Day provides an opportunity for individuals in every community to get involved in activities that can lead to better health.

The theme for 2014 is vector-borne diseases. with the slogan “Small bite, big threat”.

More than half the world’s population is at risk from diseases such as malaria, dengue, leishmaniasis, Lyme disease, schistosomiasis, and yellow fever, carried by mosquitoes, flies, ticks, water snails and other vectors. Every year, more than 1 billion people are infected and more than 1 million die from vector-borne diseases.

DEMOGRAPHIC DIVIDEND

WHAT ARE VECTORS AND VECTOR-BORNE DISEASES?Vectors are organisms that transmit pathogens and parasites from one infected person (or animal) to another.

Vector-borne diseases are illnesses caused by these pathogens and parasites in human populations.

They are most commonly found in tropical areas and places where access to safe drinking-water and sanitation systems is problematic.

The most deadly vector-borne disease, malaria, caused an estimated 660 000 deaths in 2010.

However, the world's fastest growing vector-borne disease is dengue, with a 30-fold increase in disease incidence over the last 50 years. 

World Health Day 2014 will spotlight some of the most commonly known vectors – such as mosquitoes, sandflies, bugs, ticks and snails – responsible for transmitting a wide range of parasites and pathogens that attack humans or animals.

Mosquitoes, for example, not only transmit malaria and dengue, but also lymphatic filariasis, chikungunya, Japanese encephalitis and yellow fever.

GOAL: BETTER PROTECTION FROM VECTOR-BORNE DISEASES

The campaign aims to raise awareness about the threat posed by vectors and vector-borne diseases and to stimulate families and communities to take action to protect themselves.

More broadly, through the campaign, we are aiming for the following:

families living in areas where diseases are transmitted by vectors know how to protect themselves;

in countries where vector-borne diseases are a public health problem, ministries of health put in place measures to improve the protection of their populations; and

in countries where vector-borne diseases are an emerging threat, health authorities work with environmental and relevant authorities locally and in neighbouring countries to improve integrated surveillance of vectors and to take measures to prevent their proliferation

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VECTOR ECOLOGY AND MANAGEMENT (VEM)Vector-borne diseases (VBDs) account for 16 % of the estimated global burden of communicable diseases

Vector control is an important component in the prevention and control of VBDs, especially for transmission control.

VEM, as a cross-cutting activity, develops and promotes strategies, guidelines and standards for vector control, including sound managment of pesticides.

VEM promotes integrated vector management to improve efficacy, cost-effectiveness, ecological soudness and sustainability of vector control interventions for VBD control. 

DENGUE

Key factsDengue is a mosquito-borne viral infection.

The infection causes flu-like illness, and occasionally develops into a potentially lethal complication called dengue Hemorrhagic fever and dengue shock syndrome.

The global incidence of dengue has grown dramatically in recent decades.About half of the world's population is now at risk.

Dengue is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas.

There is no specific treatment for dengue/ severe dengue, but early detection and access to proper medical care lowers fatality rates below 1%.

Dengue prevention and control solely depends on effective vector control measures.

There are four distinct, but closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4).

Recovery from infection by one provides lifelong immunity against that particular serotype.

However, cross-immunity to the other serotypes after recovery is only partial and temporary.

Subsequent infections by other serotypes increase the risk of developing severe dengue.

Global burden of dengue

The incidence of dengue has grown dramatically around the world in recent decades. Over 2.5 billion people – over 40% of the world's population – are now at risk from dengue.

WHO currently estimates there may be 50–100 million dengue infections worldwide every year.

TRANSMISSIONThe Aedes aegypti mosquito is the primary vector of dengue. The virus is transmitted to humans through the bites of infected female mosquitoes.

After virus incubation for 4–10 days, an infected mosquito is capable of transmitting the virus for the rest of its life.

Infected humans are the main carriers and multipliers of the virus, serving as a source of the virus for uninfected mosquitoes.

The Aedes aegypti mosquito lives in urban habitats and breeds mostly in man-made containers. Unlike other mosquitoes Ae. aegypti is a daytime feeder; its peak biting periods are early in the morning and in the evening before dusk.

SYMPTOMSDengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death.

Dengue should be suspected when a high fever (40°C/ 104°F) is accompanied by two of the following symptoms: severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands or rash.

DENGUE HEMORRHAGIC FEVER is a potentially deadly complication due to plasma leaking, fluid and electrolyte losses, respiratory distress, severe bleeding, thrombocytopenia ,hemoconcentration and organ impairment. Petechiae are present on extremities ,axilla,face and palate.there is easy bruisability.

Warning signs include: severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, restlessness, blood in vomit.

DENGUE SHOCK SYNDROME supervenes after 2-7 days of fever ,if not treated appropriately.

DIAGNOSIS:

Clinical diagnosis corroborated by1. raised hematocrit,2.thrombocytopenia and3. positive torniquet test.4.Four fold rise in dengue hemagglutin inhibition antibody titre or complemet fixing antibody.

TreatmentThere is no specific treatment for dengue fever.

Management of hyperpyrexia ,body pains and fluid loss constitutes the treatment.

DHF: Oral fluid intake,Anti pyretics such PCM for hyperpyrexia,early and effective replacement of plasma losses with plasma expander,fluidS and electrolytes .Transfusion of fresh blood or platelet suspended in plasma is given for severe bleeding and associated thrombocytopenia.

DSS;

-Idicates loss of body fluids by more than 10%.-immediate and rapid volume replacement is needed.-monitoring with hematocrit value,if it is raising,administer plasma or 5%albumin.-declining hematocrit s/o internal bleeding…Rx with fresh whole blood.-concentrated platelet transfusion or fresh frozen plasma is indicated in cases where coagulopathy causes massive bleeding.-Maintenance of the patient's body fluid volume is critical to severe dengue care.Immunization

There is no vaccine to protect against dengue. Developing a vaccine against dengue/severe dengue has been challenging although there has been recent progress in vaccine development.

Several candidate vaccines are in various phases of trials.

Prevention and controlAt present, the only method to control or prevent the transmission of dengue virus is to combat vector mosquitoes through:

preventing mosquitoes from accessing egg-laying habitats by environmental management and modification;

disposing of solid waste properly and removing artificial man-made habitats;covering, emptying and cleaning of domestic water storage containers on a weekly basis;

applying appropriate insecticides to water storage outdoor containers;

using of personal household protection such as window screens, long-sleeved clothes, insecticide treated materials, coils and vaporizers;

improving community participation and mobilization for sustained vector control;

applying insecticides as space spraying during outbreaks as one of the emergency vector control measures;

active monitoring and surveillance of vectors should be carried out to determine effectiveness of control interventions.

MALARIA

Caused by Plasmodium parasites.

The parasites are spread to people through the bites of infected Anopheles mosquitoes, called "malaria vectors", which bite mainly between dusk and dawn

About 3.4 billion people – half of the world's population – are at risk of malaria.

Increased prevention and control measures have led to a reduction in malaria mortality rates by 42% globally since 2000 and by 49% in the WHO African Region.

People living in the poorest countries are the most vulnerable to malaria.

There are four parasite species that cause malaria in humans:

Plasmodium falciparum,vivax,malariae,ovale;Pl vivax infection is most common,Pl falcifarum infection is deadliest

TransmissionMalaria is transmitted exclusively through the bites of Anopheles mosquitoes.

The intensity of transmission depends on factors related to the parasite, the vector, the human host, and the environment.

Transmission also depends on climatic conditions that may affect the number and survival of mosquitoes, such as rainfall patterns, temperature and humidity.

In many places, transmission is seasonal, with the peak during and just after the rainy season.

Malaria epidemics can occur when climate and other conditions suddenly favour transmission in areas where people have little or no immunity to malaria.

They can also occur when people with low immunity move into areas with intense malaria transmission, for instance to find work, or as refugees.

SymptomsMalaria is an acute febrile illness.

Symptoms appear seven days or more (usually 10–15 days)

The first symptoms – fever, headache, chills and vomiting – may be mild and difficult to recognize as malaria.

If not treated within 24 hours, P. falciparum malaria can progress to severe illness often leading to death.

Children with severe malaria frequently develop one or more of the following symptoms: severe anaemia, respiratory distress in relation to metabolic acidosis, or cerebral malaria.

In adults, multi-organ involvement is also frequent. In malaria endemic areas, persons may develop partial immunity, allowing asymptomatic infections to occur.

SYMPTOMS OF SEVERE AND COMPLICATED MALARIA

The symptoms are a history of high fever, plus at least one of the following:-

Prostration (inability to sit), altered consciousness lethargy Breathing difficulties Severe anaemia Generalized convulsions/fitscomaInability to drink/vomiting, Dark and/or limited production of urine

Patients with prostration and/or breathing difficulties should, if at all possible, be treated with parenteral antimalarials and antibiotics. .

SIGNS OF SEVERE AND COMPLICATED MALARIACerebral malaria, defined as unarousable coma not attributable to any other cause in a patient with falciparum malaria.

Generalized convulsions. ,

Normocytic anaemia.

Renal failure.

Hypoglycaemia.

Fluid, electrolyte and acid-base disturbances.

Pulmonary oedema.

Circulatory collapse and shock ("algid malaria").

Spontaneous bleeding (disseminated intravascular coagulation).

haemoglobinuria

MALARIA IN PREGNANCY

Pregnant women are particularly vulnerable to malaria as pregnancy reduces a woman’s immunity to malaria, making her more susceptible to malaria infection and increasing the risk of illness, severe anaemia and death.

For the unborn child, maternal malaria increases the risk of spontaneous abortion, stillbirth, premature delivery and low birth weight - a leading cause of child mortality

Based on available evidence, WHO recommends a three pronged approach to treat malaria in pregnancy

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Insecticide-treated nets (ITNs),

Intermittent preventive treatment

Effective case management of malarial illness

LABORATORY DIAGNOSIS.

1.Microscopic examination of blood film:

Thick smear for quick detection of parasites and thin smear for species

2.DETECTION OF HISTIDINE RICH PROTEIN-2

3.LACTIC DEHYDROGENASE ANTIGENS

4.QUANTITATIVE BUFFY COAT METHOD.

5. POLYMERASE CHAIN REACTION.

6. SEROLOGY

TREATMENT.UNCOMPLICATED MALARIA.A. Vivax malaria: chloroquine for 3

days+primaquine for 14 days.B. In chloroquine resistant cases

quinine+doxycyclin for 7 days+primaquine for 14 days.

C. Chloroquine sensitive falciparum malaria: chloroquine for 3 days +primaquine single dose.

D. Chloroquine resistant falciparum malaria:artesunate for 3 days+sulfadoxine-pyrimethamine single dose (or),artesunate 3 days+mefloquine on 2 and 3rd day,(or ) quinine +doxycycline for 7 days.COMPLICATED MALARIA.

I V Quinine sulphate for 7 days DOC.I V Artesunate,arteether,artemether for 7 days…

Prevention -WHO StrategyVector control is the main way to reduce malaria transmission at the community level.

Intervention that can reduce malaria transmission from very high levels to close to zero.

For individuals, personal protection against mosquito bites represents the first line of defence for malaria prevention.

Two forms of vector control are effective in a wide range of circumstances.

Insecticide-treated mosquito nets (ITNs)Long-lasting insecticidal nets (LLINs) are the preferred form of ITNs for public health distribution programmes.

WHO recommends coverage for all at-risk persons; and in most settings.

The most cost effective way to achieve this is through provision of free LLINs, so that everyone sleeps under a LLIN every night.

Indoor spraying with residual insecticidesIndoor residual spraying (IRS) with insecticides is a powerful way to rapidly reduce malaria transmission.

Its full potential is realized when at least 80% of houses in targeted areas are sprayed.

Indoor spraying is effective for 3–6 months, depending on the insecticide used and the type of surface on which it is sprayed. DDT can be effective for 9–12 months in some cases

Insecticide resistance

Much of the success to date in controlling malaria is due to vector control.

In recent years, mosquito resistance to pyrethroids has emerged in many countries. In some areas, resistance to all four classes of insecticides used for public health has been detected.

Fortunately, this resistance has only rarely been associated with decreased efficacy, and LLINs and IRS remain highly effective tools in almost all settings.

Vaccines against malariaThere are currently no licensed vaccines against malaria or any other human parasite.

One research vaccine against P. falciparum, known as RTS,S/AS01, is most advanced.

This vaccine is currently being evaluated in a large clinical trial in 7 countries in Africa.

A WHO recommendation for use will depend on the final results from the large clinical trial.

These final results are expected in late 2014, and a recommendation as to whether or not this vaccine should be added to existing malaria control tools is expected in late 2015.

MALARIA CONTROL STRATEGIES UNDER NVBDCP-GOVT OF INDIA.

1. Early case Detection and Prompt Treatment (EDPT)

EDPT is the main strategy of malaria control - radical treatment is necessary for all the cases of malaria to prevent transmission of malaria.

Chloroquine is the main anti-malaria drug for uncomplicated malaria.

Drug Distribution Centres (DDCs) and Fever Treatment Depots (FTDs) have been established in the rural areas for providing easy access to anti-malarial drugs to the community.

Alternative drugs for chloroquine resistant malaria are recommended as per the drug policy of malaria.

2. Vector Control

(i) Chemical ControlUse of Indoor Residual Spray (IRS) with insecticides recommended under the programnme

Use of chemical larvicides like Abate in potable water

Aerosol space spray during day time

Malathion fogging during outbreaks(ii) Biological Control

larvivorous fish Gambusia in ornamental tanks, fountains , Use of biocides.etc.

(iii) Personal Prophylatic Measures Use of mosquito repellent creams, liquids, coils, mats etc.Screening of the houses with wire meshUse of bednets treated with insecticideWearing clothes that cover maximum surface area of the body

3. Community ParticipationSensitizing and involving the community for detection of Anopheles breeding places and their eliminationNGO schemes involving them in programme strategiesCollaboration with CII/ASSOCHAM/FICCI

4. Environmental Management & Source Reduction MethodsSource reduction i.e. filling of the breeding places

Proper covering of stored water

Channelization of breeding source

5. Monitoring and Evaluation of the programmeMonthly Computerized Management Information System(CMIS)

Field visits by state by State National Programme Officers

Field visits by Malaria Research Centres and other ICMR Institutes

Feedback to states on field observations for correction actions.

CHIKUNGUNYAKey factsChikungunya is a viral disease transmitted to humans by infected mosquitoes.

It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.

The disease shares some clinical signs with dengue, and can be misdiagnosed in areas where dengue is common.

There is no cure for the disease. Treatment is focused on relieving the symptoms.

The proximity of mosquito breeding sites to human habitation is a significant risk factor for chikungunya.

The disease occurs in Africa, Asia and the Indian subcontinent. In recent decades mosquito vectors of chikungunya have spread to Europe and the Americas.

JAPANESE ENCEPHALITISKey factsJapanese encephalitis (JE) is a flavivirus related to dengue, yellow fever and West Nile viruses, and is spread by mosquitoes.

JE is the main cause of viral encephalitis in many countries of Asia with nearly  68 000 clinical cases every year.

Although symptomatic JE is rare, the case-fatality rate among those with encephalitis can be as high as 30%. Permanent neurologic or psychiatric sequelae can occur in 30%–50% of those with encephalitis.

24 countries in the WHO South-East Asia and Western Pacific regions have endemic JE transmission, exposing more than 3 billion people to risks of infection.

There is no cure for the disease. Treatment is focused on relieving severe clinical signs and supporting the patient to overcome the infection.

Safe and effective vaccines are available to prevent JE. WHO recommends JE vaccination in all regions where the disease is a recognised public health problem.

LEISHMANIASISKey facts

There are three main forms of leishmaniases – visceral (often known as kala-azar and the most serious form of the disease), cutaneous (the most common), and mucocutaneous.

Leishmaniasis is caused by the protozoan Leishmania parasites which are transmitted by the bite of infected sandflies.

The disease affects the poorest people on the planet, and is associated with malnutrition, population displacement, poor housing, a weak immune system and lack of resources.

Leishmaniasis is linked to environmental changes such as deforestation, building of dams, irrigation schemes and urbanization.

An estimated 1.3 million new cases and 20 000 to 30 000 deaths occur annually.

YELLOW FEVERKey factsYellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes.

The "yellow" in the name refers to the jaundice that affects some patients.

Up to 50% of severely affected persons without treatment will die from yellow fever.

There are an estimated 200 000 cases of yellow fever, causing 30 000 deaths, worldwide each year, with 90% occurring in Africa.

The virus is endemic in tropical areas of Africa and Latin America, with a combined population of over 900 million people.

The number of yellow fever cases has increased over the past two decades due to declining population immunity to infection, deforestation, urbanization, population movements and climate change.

There is no specific treatment for yellow fever.

Treatment is symptomatic, aimed at reducing the symptoms for the comfort of the patient.

Vaccination is the most important preventive measure against yellow fever.

The vaccine is safe, affordable and highly effective, and a single dose of yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease and a booster dose of yellow fever vaccine is not needed.

The vaccine provides effective immunity within 30 days for 99% of persons vaccinated.