Tips for prevention of breeding of Aedes mosquito in your urban neighbourhood

Dengue fever is an acute febrile illness which can be life threatening.The WHO says some 2.5 billion people, two fifths of the world's population, are now at risk from dengue and estimates that there may be 50 million cases of dengue infection worldwide every year.
Dengue is transmitted by Aedes mosquitoes, particularly A. aegypti and A. albopictus.So it is very important for us to know about these mosquitos and to learn how to prevent its breeding in our neighbourhood.

Dengue Virus Transmission


Dengue viruses are transmitted to humans through the bites of infective female Aedes mosquitoes. The mosquitoes generally acquire the virus while feeding on the blood of an infected person. After virus incubation for eight to ten days, an infected mosquito is capable, during probing and blood feeding, of transmitting the virus for the rest of its life. There is no way to tell if a mosquito is carrying the dengue virus. Infected female mosquitoes may also transmit the virus to their offspring by transovarial (via the eggs) transmission, but the role of this in sustaining transmission of the virus to humans has not yet been defined.

Aedes aegypti goes through a complete metamorphosis with an egg, larvae, pupae, and adult stage. The adult life span can range from two weeks to a month depending on environmental conditions. The life cycle of Aedes aegypti can be completed within one-and-a-half to three weeks
 


After taking a blood meal, female Aedes aegypti mosquitos produce on average 100 to 200 eggs per batch. The females can produce up to five batches of eggs during a lifetime. The number of eggs is dependent on the size of the bloodmeal. Eggs are laid on damp surfaces in areas likely to temporarily flood, such as tree holes and man-made containers like barrels, drums, jars, pots, buckets, flower vases, plant saucers, tanks, discarded bottles, tins, tyres, water cooler, etc. and a lot more places where rain-water collects or is stored. The female Aedes aegypti lays her eggs separately unlike most species. Not all eggs are laid at once, but they can be spread out over hours or days, depending on the availability of suitable substrates. Eggs will most often be placed at varying distances above the water line. The female mosquito will not lay the entire clutch at a single site, but rather spread out the eggs over several sites.


The eggs of Aedes aegypti are smooth, long, ovoid shaped, and roughly one millimeter long. When first laid, eggs appear white but within minutes turn a shiny black. In warm climates eggs may develop in as little as two days, whereas in cooler temperate climates, development can take up to a week. Laid eggs can survive for very long periods in a dry state, often for more than a year. However, they hatch immediately once submerged in water. This makes the control of the mosquito very difficult.

Prevention of breeding of Aedes mosquito

Aedes mosquito lay their eggs in clear,clean water and not in contaminated water.As they fly only a few metres their breeding place is usually in our house itself.

Most common breediing places and tips to prevent breeding

Water storage tank/cistern ---should have mosquito proof lids
water coolers/collection pans in Fridge/ACs ------ water should be drained out periodically 

Drum   ------tight lids
Flower vase with water  [least in brass vase]----------change water frequently,use sand
Potted plants with saucers ------- change water frequently
Ornamental pool/fountain ---------water changed once a week
Roof gutter/sun shades------------check frequently for drain block
Animal water container----------- empty and clean periodically
Ant trap--------------------------use oil/salt
Used tyres-----------------------keep it under roof
Discarded large appliances-------bury or keep it under roof 
Discarded buckets,plastic cups,tin cans etc-----bury


Whenever piped water supply is inadequate and available only at restricted hours or at low pressure, the storage of water in varied types of containers is encouraged, thus leading to increased Aedes breeding.It is essential that potable water supplies be delivered in sufficient quantity, quality and consistency to reduce the necessity and use of water storage containers that serve as the most productive larval habitats.

Chemical and biological agents can also be used for prevention of breeding of Aedes mosquito.

from
Denguevirusnet
WHO

Feverish Rainy Season

The Monsoon is here.Though it really began pouring down only last week the Fever season started by early June. OPDs are overflowing and it is hard to get a hospital bed.
What kind of fevers are more commonly seen this year?
The usual influenza like upper respiratory tract infection is the commonest but the more serious fever this year is Dengue fever.Chikungunya fever is less common when compared to last year.
Dengue Fever[DF]
Dengue is a mosquito-borne infection that in recent decades has become a major international public health concern. Dengue is found in tropical and sub-tropical regions around the world, predominantly in urban and semi-urban areas.As per current estimates, availability of at least 100 countries are endemic for DF and about 40% of the world population (2.5 billion people) are at risk in tropics and sub-tropics. As per estimates, over 50 million infections with about 400,000 cases of DF are reported annually which is a leading cause of childhood mortality in several Asian countries.

Dengue is transmitted by the bite of an Aedes mosquito infected with any one of the four dengue viruses. Symptoms appear 3—14 days after the infective bite. Dengue fever is a febrile illness that affects infants, young children and adults.
Symptoms range from a mild fever, to incapacitating high fever, with severe headache, pain behind the eyes, muscle and joint pain, and rash. There are no specific antiviral medicines for dengue. It is important to maintain hydration. Use of acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs (e.g. Ibuprofen) is not recommended.
Dengue hemorrhagic fever (fever, abdominal pain, vomiting, bleeding) is a potentially lethal complication, affecting mainly children. Early clinical diagnosis and careful clinical management by experienced physicians and nurses increase survival of patients.
My Experience
When a patient presents with sudden appearance of high grade fever and headache without congested nose or cough my thoughts are about Dengue fever.If there is severe joint pain and swelling especially of small joints of hand I may consider Chikungunya as the first possibility.
I will then order a Complete Blood Count. A low total WBC count along with low Platelet count make my suspicion of Dengue fever stronger. Chikungunya fever may also have a low WBC count but the Platelets are usually not very low.
I admit the patient if the Platelet count is below 100000 or if the patient looks very sick. Maintaing hydration and blood pressure is most important. I had more than 20 patients with suspected Dengue fever since the beginning of June, but only one had the complication of Dengue hemorrhagic fever.There were no loss of life.

Diagnosis of Dengue fever is mainly by clinical features and not by laboratory methods.By the time the antibody levels rises and is detectable by blood tests the disease would have subsided.

Prevention of Dengue fever is mainly by reducing the mosquito breeding.Aedes breeds primarily in man-made containers like earthenware jars, metal drums and concrete cisterns used for domestic water storage, as well as discarded plastic food containers, used automobile tyres and other items that collect rainwater.
Vector control is implemented using environmental management and chemical methods. Proper solid waste disposal and improved water storage practices, including covering containers to prevent access by egg-laying female mosquitoes are among methods that are encouraged through community-based programmes.
The application of appropriate insecticides to larval habitats, particularly those that are useful in households, e.g. water storage vessels, prevents mosquito breeding for several weeks but must be re-applied periodically. Small, mosquito-eating fish and copepods (tiny crustaceans) have also been used with some success.
Fever season is always a challenge for an Internist like me. I love that challenge. Hope I can rise up to it.

Chronic severe Joint pain of Chikungunya

The rainy season due to the South West Monsoon over the Indian sub continent is over.Epidemic of acute severe joint pain and swellings associated with fever due to Chikungunya infection has also subsided.Now I am seeing more and more patients with Chronic severe joint pain of varying duration, a sequel of Chikungunya infection.

Let me tell you a little more about this virus and the illness it causes in humans.

Chikungunya is a re-emerging, mosquito-borne viral infection causing fever, rash and acute or sudden severe joint pains of several joints.Chikungunya (Chick’-en-GUN-yah) in Swahili an African language meaning “that which contorts or bends up” refers to the contorted (stooped) posture of patients who are afflicted with severe joint pains (arthralgia) the most common feature of the disease.
Chikungunya virus is a single-stranded RNA Alphavirus, from the family Togaviridae. Other Alphaviruses also causing fever, rash and arthralgia, include O’nyong-nyong, Mayaro,Barmah Forest, Ross River and Sindbis viruses. Chikungunya virus is most closely related to O’nyong-nyong, but remains genetically distinct.

The disease was first described by Marion Robinson and W.H.R. Lumsden, following an outbreak along the border between Tanzania(erstwhile Tanganyika) and Mozambique, in1952. Since 1953, the virus has caused outbreaks in Africa and South Eastern Asia, including India, Sri Lanka, Myanmar, Thailand, Indonesia, the Philippines and Malaysia, which are well documented. There is historical evidence that Chikungunya virus originated in Africa and subsequently spread to Asia. Phylogenetic studies support this theory, with Chikungunya virus strains falling into three distinct genotypes based on origin from West Africa, Central/East Africa or Asia.

Chikungunya is transmitted by the bite of the infected Aedes mosquito from an infected person to a healthy person. The disease does not get transmitted directly from human to human (i.e. it is not a contagious disease). In a pregnant woman with Chikungunya there is risk of transmitting the disease to her foetus.
The fever starts usually about 2 to 3 days after the entry of virus into the human body. There will be severe chills and shaking of the body at the onset of fever.At the same time the joint pain and swelling starts.The patient will not be able to move with in minutes of onset of illness.The joints of hands mainly the metacarpo phalangeal and proximal inter phalangeal joints become warm swollen and very painful.Wrist and elbow are also affected to a lesser extend.The joints of ankle,feet and to a lesser extend hip are all affected.
Itchy reddish raised rash is typically seen[70%] when the fever subsides, which in most of my patients was by 3 days.Many patients and Physicians confuse it with drug rash due to allergy to the medicines the patient took for fever and joint pain.
Rash is typically seen on the cheeks, nose and outer part of ears.The ear lobe is typically painful to touch. The rash is also seen over the trunk and limbs with severe itching which lasts for only 2 days. There will be painful swelling of ankle and shin with dark red discoloration. Painful oral ulcers are also seen during this time.Last year I had few patients with enlarged cervical lymph nodes, which disappeared in few days.

Although rare, the infection can result in meningo-encephalitis, especially in newborns and those with pre-existing medical conditions. Pregnant women can pass the infection to their foetus. Severe cases of Chikungunya can occur in the elderly, in very young ones (newborns) and in those who are immuno-compromised.

Chikungunya outbreaks typically result in several hundreds or thousands of cases but deaths are rarely encountered.
Differential diagnosis of Chikungunya includes Dengue and Dengue Haemorrhagic Fever,
O’nyong-nyong virus infection and Sindbis virus infection.
It has been reported that attack rates in susceptible populations may be as high as 40-85 per cent and the ratio of symptomatic to asymptomatic patients is about 1.2:1.

Children are less likely to experience joint pain, but may have other features such as febrile fits, vomiting, abdominal pain and constipation.

The discoloration of the nose usually lasts for months.I call it the seal of Chikugunya as I can identify a person who had Chikungunya in the recent past seeing that seal.
Some patients may remain feverish for some more days. The joint pain become less in few days. In about 60 percent of the patients the ilness including the joint pains last only about a week.They become completly all right with only a little bit of tiredness remaining.
But in about 40% of patients joint pain increases or persists.The chronic joint pain of Chikungunya resembles that of Rheumatoid arthritis. The joints commonly involved are the wrists and the knees.The ankle and smaller joints of feet and hands are also involved.Stiffness of these joints in the morning lasting more than 30 mts is typical. The patient feels better as he/she continues to move the joints.
The joint stiffness and pain lasts for about 3 months in about 30% of patients in my practise. But in an unfortunate 10% it may last indefinitely.

Lab Diagnosis of Chikungunya fever

Virus isolation and PCR techniques are costly and is available in very few centres. Serological diagnosis is possible only after a week of onset by detecting antibodies. As the treatment is mostly symptom specefic diagnosis will not alter patient management much. So the typical triad of fever, acute onset joint pains and rash along with a low white cell count in blood sample is sufficient enough to diagnose Chikungunya fever

Treatment of Chikungunya fever

Paracetamol 10 to 15mg per kg body weight given 3 to 4 times a day reduces the fever.It is needed only in the first 2 to 3 days of illness.

Non Steroidal anti inflammatory agents have to be given liberally to reduce the pain and swelling. This may have to be continued for few weeks in some patients with persistent joint pain. Renal and Gastric safety have to ensured while taking such medicines.
Short course of steroids like Prednisolone also helps in resistant cases.
Other analgesics like Tramadol are also useful.
Disease modifying anti rheumatic agents like Chloroquine have been found useful in some studies.Personally I feel Chloroquine is not of much help as it is a slow acting drug taking almost 3 months to be fully effective.

Most of the patients who turned to alternative systems of medicine for relief came back to me saying there is no relief to pain.Many had to take NSAIDs along with their Ayurvedic and Homeopathic medicines which proved that other systems have nothing much to offer.

In short Chikungunya fever is easy to diagnose but not that easy to treat, but to those who suffer it is pure hell.

Rain

Though late, the South-West monsoon [the main source of Rain for this area] finally have been kind enough to my native state, Kerala.

Until this week, Newspapers were saying that this was the weakest monsoon in recent memory with a 43 percent deficit in rainfall in the first 7 weeks of the season. Power blackouts started [as the major source of Power here is Hydro-electric projects] and fear of failed crops were looming large.
This week everything changed. The sky started pouring and pouring. Even as I type, I can hear the wonderful sound of rain. Newspapers started talking about flash floods and landslips. Let us hope the monsoon will wipe off the rainfall deficit in quick time.

Rain or no Rain,Chikungunya epidemic continues relentlessly. In some families, almost all members are getting affected. I had an opportunity to visit a small town 15 kms away. I went there on invitation of a local Club. They wanted me to give a health education class about chikungunya fever.
When I reached there, the people were not in a mood to listen to a talk. They wanted prescription for medicines so that they can recover fast. Most of them were manual labourers, and the persistent joint pain and swellings were preventing them from working. Some wanted preventive medicines to protect them from the virus. I was helpless. There is no fast cure.The joint pains may last for weeks to months. During that period, they will have to continue taking anti-inflammatory drugs. Also, there is no preventive medicine or vaccine yet. I asked them to take measures to reduce breeding of Aedes mosquito. I also asked them to isolate the patient inside a mosquito net during the time of fever. At that time, maximum number of viruses are there in patient's blood and mosquito bite can easily spread the illness.
My team saw more than 50 patients. Some free medicines were distributed, but nobody was satisfied. As we drove back, my thoughts were on the enormity of physical and economic damage this virus had brought on the society, especially for the poor.

Acute severe joint pain

She was a 30 year old housewife. She was literally carried in to my consulting room by her husband and her mother. She was writhing with agony at each movement of her joints.

She was perfectly all right in the morning.She walked down to the river[which was about 1/2 kilometre away] to bath, came back and made coffee.At that moment,before she could serve coffee her joint pain started with shivering and she had to be carried from kitchen to bedroom.

She had pain in small joints of fingers, wrist,elbow, shoulders,hip,knee and ankles. All those joints were warm. Her temperature was 101F. Rest of the examination was normal.

Yes, this is the classical onset of Chikungunya fever. I send her out in a wheel chair to get admitted.She was given medicines to reduce fever and inflammation of joints.The next day she was sitting happily ready to go home. Her fever has subsided and joint pains less.She will continue to suffer from joint pains for uncertain number of weeks, and thus may need to continue anti inflammatory drugs.



The fever and joint pains in chikungunya infection start so suddenly that some patients are able to tell the exact minute of onset. I still wonder why the onset is so sudden and unexpected.

Chikungunya fever on the rise

Rainy season[monsoon] is here and more and more patients are coming with fever. Many come with sudden rise in temperature, chills, and severe joint pains. As the fever subsides, in few days a itchy skin rash develops. In many, the joint pain and swellings last for weeks to months and sometime years. This is Chikungunya fever.
Chikungunya fever is an easy diagnosis for doctor working in an epidemic setting. After seeing a few patients and following them up it is difficult to miss, but it is a painful diagnosis for the patient. Some who had it last June are still suffering from joint pain and stiffness.

Today I saw about 8 acute chikungunya fever patients and a few chronic joint pain patients due to chikungunya.

More patients now are coming from within 2 kilometres of my clinic/home.
Hope I wont be the next victim.