mosquito

Beware of repeated dengue afflictions

Docs Warn That Fatality Risk Increases Due To Reaction Between Antibodies Present In The Body From Primary & Secondary Infections
Even as dengue ravages Kerala, health experts are confused by the uncommon traits and complications that were recently observed in patients.

The pattern of dengue deaths also indicates that mortality rate was high among patients who were repeatedly diagnosed with the disease.

If a person gets dengue for the first time (type-I), proper rest and medication will help in combating fever and antibodies will be generated in the body that will give life-long immunity against the type-I variety. But, when the same person is exposed to mosquito bites and gets dengue (type-II or type-III), a new set of antibodies will be generated in the body. Antibodies generated in the primary infection and secondary infection react, resulting in grave complications that may even lead to the death of the patient.

Through virus uptake and replication, type-I antibodies will intensify and complicate the typeII virus by a process called antibody dependent immune enhancement. “When a person is tested positive for dengue, prescribed antibiotics will only treat the symptoms of fever and not the virus.Like any other viral fever, dengue virus will subside and antibodies will be generated in a week. When a person is affected by dengue twice or thrice, the reaction of subsequent antibodies will lead to internal bleeding and cause dengue haemorrhagic fever or dengue shock syndrome that may lead to death,” said associate professor of community medicine at Thiruvananthapuram medical college Dr Althaf A.

The scattered information and diagnoses are yet to be compiled and analysed by authorities. Sources in the health department said there was no proper database or research on such complexities.

“When autopsy was conducted in a suspected case of dengue death in 2013, we found that the person was suffering from West Nile fever, a mosquito-borne disease. Similarly , all reported deaths might not be due to dengue. We are unable to contain deaths as scientific analysis and research are lacking,” said Dr Althaf.

There are four different strains of dengue and for a person repeatedly afflicted with dengue, the risk factor goes up. “Severe internal bleeding or blood loss can occur due to the reaction of antibodies already present in hisher body . This is a matter we have to address through research,” said former state nodal officer (communicable diseases) Dr Amar Fettle.

Genetic mutation in disease causing virus is also suspected to be one of the major reasons for the increase in fatalities, said experts. “The spontaneous changes in genetic coding of dengue causing virus can be one of the reasons for the complications.Similar to the mutation seen in H1N1 virus, dengue causing virus is suspected to have undergone genetic mutation. H1N1 virus was seen only in animals at first, it later it was transmitted to humans and by 2008, due to mutation, H1N1 virus was transmitted from one human to another,” said Dr Althaf.

Doctors, who treat dengue, have also no ticed the change in symptoms. “Many patients who seek treatment for diarrhoea; throat pain and vomiting are later diagnosed with dengue. The symptoms were high fever, back and abdominal pain. It is not the same now,” said a doctor at the general hospital in the capital on condition of anonymity .

“The Aedes aegypti mosquitoes are responsible for the outbreak.These mosquitoes can cause chikungunya, yellow fever and Zika fever.Our environment is very receptive to these diseases and we are vulnerable,” he said.

Dengue cases have risen in Thiruvananthapuram, Kollam, Alappuzha, Palakkad, Malappuram and Kozhikode this year and the disease has become round-the-year problem over the past three years.

Source: THE TIMES OF INDIA

Behavioral Resistance: Mosquitoes Learn to Avoid Bed Nets

Malaria is a notoriously tricky infectious disease. Because of a unique genetic flexibility, it is able to change surface proteins, avoiding the immune response and greatly complicating vaccine development. Furthermore, the parasite is transmitted by mosquitoes, which are difficult to control. Insecticides work, but mosquitoes can develop resistance to them.

One method widely used to control malaria is for governments or charities to provide families with insecticide-treated bed nets. Overall, this strategy is very successful, and it has been credited with preventing some 451 million cases of malaria in the past 15 years. But bed nets are not successful everywhere. In some parts of the world, mosquitoes develop “behavioral resistance”; i.e., they learn to avoid bed nets by biting people earlier in the day.

A team led by Lisa Reimer of the Liverpool School of Tropical Medicine monitored mosquito behavior in villages in Papua New Guinea before (2008) and after (2009-2011) the distribution of bed nets. Data from one of the villages, Mauno, depicts a very noticeable shift in mosquito feeding behavior.

Before bed nets were distributed in 2008, the median biting time for mosquitoes was around midnight. After the distribution, the median time shifted back to 10 pm. Also, a greater proportion of mosquitoes took their dinner even earlier, from 7 to 9 pm.

Worryingly, it’s unclear whether the bed nets were effective at preventing malaria transmission. The number of bites per person per night dropped after the introduction of bed nets, but started to climb in subsequent years as mosquitoes began to adapt. Additionally, the prevalence of malaria infection in humans — arguably, the only statistic that actually matters — dropped in one village, remained the same in a second, and ticked up slightly (albeit insignificantly) in a third.

Despite the mixed results in Papua New Guinea, Dr Reimer believes that bed nets should continue to be used worldwide as part of a mosquito control strategy. However, she notes that behavioral resistance may prove just as vexing as insecticide resistance and, in some locations, may limit the efficacy of bed nets.

Thus, mosquitoes must be monitored for both behavioral and insecticide resistance, as the little creeps stubbornly refuse to die and may be cleverer than we thought.

Source: Edward K. Thomsen et al. “Mosquito behaviour change after distribution of bednets results in decreased protection against malaria exposure.”

Source : Acsh.org

Dengue Claimed 179 Lives, no Death Due to Chikungunya: Government

Dengue has claimed 179 lives across the country this year while no death has been reported due to chikungunya, though it affected 21,000 people, the Rajya Sabha was told today.

“During 2016 (till November 13), a total number of 179 deaths due to dengue and no death due to chikungunya has been reported in the country.

“The number of positive cases for dengue and chikungunya in the country during 2016 (till November 13) are 90,277 and 21,094 respectively,” Health Minister J P Nadda said in a written reply.

He said the reason behind the steep increase in the number of cases are– water storage practices, poor solid waste management, construction activities, large migratory population, inadequate vector management and lack of protective immunity in the affected population.

Dengue claimed 33 lives in Uttar Pradesh, 28 in West Bengal and 22 in Maharashtra, he said. Replying to another question on the same issue, Minister State for Health Faggan Singh Kulaste said the government has taken measures for prevention and control of dengue and chikungunya in the country, including in Delhi.

He said technical guidelines for prevention and control, clinical management and vector control have been issued to states and UTs while periodic reviews have taken place.

Since January, 2016, 22 review meetings at the levels of Minister, secretary and others were held.

He said since January 12 advisories have been issued at the levels of Secretary (H&FW) and Additional Secretary while states were requested to declare dengue as notifiable disease.

“States were requested to curtail out of pocket expenditure by fixing the rate for testing at Rs 600,” he said.

He said dengue and chikungunya diagnosis is provided through 542 Sentinel Surveillance Hospitals (SSHs) and 15 Apex Referral laboratories (ARLs) identified across the country.

“First version draft of ‘Strategy and Plan of action for Effective Community Participation for Prevention and Control of Dengue’ has been uploaded. A user-friendly App ‘India Fights Dengue’ has been launched while National Dengue Day has been observed on May 16, 2016 throughout the country,” he said.

Source : Smartcooky

School children work on project to fight dengue

BERHAMPUR: At a time when the state is grappling with dengue, students of MM High School, Girishola here have prepared a project to fight the disease.

The project has suggested plantation of marigold, lemon grass and podina (meant) sapling on open spaces of the villages and houses to drive away the mosquito species like aedes and anopheles responsible for diseases like dengue, malaria and chikungunya.

The project ‘Killer dengue in Girishola – a case study, remedy and solution’ has been prepared by five students of Class VIII with active guidance of the science teacher Raghunath Ghadei. It has been selected for National Children’s Science Congress (NCSC) to be held at Vidya Pratishthan’s Institute of Information Technology (VIIT), Baramati, in Maharashtra from December 27 to 31.

The project also suggested development of culture centres of dragonfly and Gambusia fish to prevent increase of mosquito population. “While we have experimented by planting the marigold herbs on the premises of our school, we came to know from the elder persons about the role of dragonfly to kill the small mosquitoes during the preparation of the project,” said P Veketesh, a student involved in the project.

The fragrance of the herbs of marigold, lemon grass and meant can prevent entry of mosquitoes to a particular area, said the guide of the project. Other students, who participated in the preparation of the project, are Rahul Moharana, Balaram Sahu, Asish Moharana and Shankar Pradhan while science supervisor Gopal Krushna Panda was actively involved in the experiments.

While a single dragonfly can eat over 30 mosquitoes a day, its larva also gulps the larva of mosquito, said Ghadei. Similarly the Gambusia fish also eats the larva of mosquito. The students of the high school mooted the project after 200 people were affected by dengue killing six persons in Girishola in July and August.

The team members toured the village and interacted with several victims to know their garbage disposal method. The village along Odisha-Andhra Pradesh border has no space for garbage disposal as the NH-16 passes in one side while railway track is on the other side. In other two sides, there are state highways. The school students along with villagers took 15 days to clean the garbage.

Times of India

Cities account for 60% of state’s dengue casualties this year

MUMBAI: Around 60% of dengue deaths in the state this year have been reported from urban areas. An analysis of the confirmed cases by the state’s health department also revealed that nearly two-thirds of the positive cases were from the urban areas.

The Mumbai Metropolitan Region, Pune, Nashik and Aurangabad have reported nearly 70% of the 5,391 dengue cases this year. The state’s figures also show a 63% jump in dengue cases between January and October this year when compared with the corresponding period last year. Out of the 22 deaths this year, 13 have been reported from the urban areas.

Mumbai alone has reported nearly 1,000 cases and four confirmed cases. However, more than 10,000 people have been hospitalised during monsoon for suspected dengue or similar illnesses. Speaking to TOI, head of the directorate of health services Dr Satish Pawar said, “It is particularly worrying because only 40% of our population resides in the urban areas. But, we have found out that construction activities are not the sole reason for the growing incidence of dengue. In certain cases where dengue had become complicated, doctors have used aggressive treatment where it was not required. Some of these hospitals were in big cities”.

Pawar added that the state has drawn up uniform treatment protocols and even trained doctors but the indiscriminate use of platelets continues to be an issue. The BMC had, in an analysis last year, found out that the use of platelets rose by 14-15% during months when dengue peaked in the city. This year, however, the situation was much better. A civic official said the use of platelets during dengue was closely monitored. “This year, there was no unusual demand for platelets,” the official said.

Times of India

Dengue cases grew by 63% in Maharashtra this year

The number of dengue cases in Maharashtra rose 63% between January and October this year compared to the same period last year. The number of deaths have remained the same, with 22 deaths in the comparative periods for 2015 and 2016.

Dengue is transmitted by the aedes aegypti-species of mosquito and has become a major public concern in the past two months, doctors said. A total of 5,653 cases were reported by the state epidemiology department this year as compared to 3,461 cases last year, with cases coming from cities like Mumbai, Kalyan-Dombivli, Pune and Nashik, said Dr Kanchan Jagtap , joint director of health services of the state.

“Every year, there is an increase in the number of dengue cases post monsoon. Moreover, the increase in construction sites have created an ideal environment for mosquito breeding,” she said.

Although the number of dengue cases has gone up, not everyone who is infected with the virus develops complications, said doctors. “Say out of 100 people infected with dengue, only 10 show complications such as a drop in blood pressure, severe drop in n platelet counts, ”said Dr Pradeep Shah, physician, Fortis Hospital, Mulund.

“Most of the patients who show complications are people who have had dengue in the past, young children, elderly and pregnant women. These are the vulnerable groups,” he said.

Doctors also said state data could be giving an incomplete picture of the dengue situation, because only those cases where the patient has tested positive for dengue infection using the ELISA (enzyme-linked immunosorbent assay) method of testing are counted as confirmed. “We treat so many patients who have all symptoms of dengue infection, but their blood test reports for ELISA test are negative. These numbers are not accounted for in the state’s data,” said Dr Altaf Patel, director of medicine Jaslok Hospital.

October 2016

Kalyan-Dombivali Municipal Corporation

Number of cases 63 number of deaths 5

Mira-Bhayander Municipal Corporation

Number of cases 33 number of deaths 2

Brihanmumbai Municipal Corporation

Number of cases 941 number of deaths 2

Source : Hindustantimes.com

Florida’s Fight Over GM Mosquitoes Going to a Vote

Scientists say there is strong evidence that the Zika virus can be controlled by releasing genetically modified male mosquitoes into the wild so they can mate with the disease-spreading females to produce sterile offspring.

But plans for a trial run in Key Haven, Fla., an unincorporated community just east of Key West, have been so controversial that officials decided to put it to a public vote.

Tuesday’s referendum is non-binding, but will weigh heavily on whether the Florida Keys Mosquito Control District proceeds with the test, which was approved by the U.S. Food and Drug Administration in August.

The genetically modified mosquitoes have been tested in Brazil, Panama and the Caymen Islands, where they reduced the wild population of Zika-bearing Aedes aegypti mosquitoes by more than 90 percent, according to British biotechnology company Oxitec, which developed the engineered strain of mosquitoes.

“In comparison, current technologies such as insecticides are only 30-to 50 percent effective at best,” Oxitec spokesman Matthew Warren told Seeker.

In addition to the Zika virus, which can cause birth defects and other disorders, Aedes aegypti mosquitoes are responsible for the spread of dengue and chikungunya. It’s the female mosquitoes that do the biting, spreading disease in their wake.

Oxitec’s solution is to engineer a gene in the males, which are then released into the wild so they can mate with the females. Any offspring that result from the union will carry an engineered “kill switch” and die before maturing enough to mate or bite, drastically reducing the population.

“We have now released more than 180 million of our male self-limiting mosquitoes worldwide. And there have been no reports of adverse impacts in any of these releases,” Warren said.

The trial in the Florida Keys would be the first in the United States.

“The genetically modified mosquitoes are incredibly promising. They’ve been incredibly successful in many of the cases where they’ve been tested for Zika so far. I think that they have tremendous promise in the United States, but there are obviously a lot of fears,” ecologist Colin Carlson, with the University of California, Berkeley, told Seeker.

Among those opposed to the Florida trial is a group of physicians, led by Dr. John Norris, who have questions about whether Oxitec’s mosquitoes, which are dependent on the antibiotic tetracycline to survive, will end up spreading antibiotic-resistant bacteria.

“We do not know what to expect when millions of mosquitoes are released on small neighborhoods possibly covered in resistant germs,” the doctors wrote in a petition to the Florida Keys Mosquito Control Board.

If the board decides to proceed with the trial, the doctors want to conduct a study to see if residents have altered bacterial resistance patterns.

Whether the referendum passes or not, one thing is certain: the spread of the Zika virus in South Florida is growing.

“We’re still trying to figure out how severe it’s going to be,” Carlson said. “From a public health perspective, it’s not a great situation.”

Pending approval by the Florida Keys Mosquito Control District, Oxitec’s test could begin next year.

Seeker.com

Here are some important facts about Dengue and Chikungunya

In a recent report, the MCD has confirmed as many as 2,711 dengue cases till October 8 as the situation remains critical.

New Delhi: Dengue and chikungunya have struck fear in Delhi so much that the health graph of the city has registered a steep rise in these cases of late.

In a recent report, the MCD has confirmed as many as 2,711 dengue cases till October 8 as the situation remains critical across the country.

With these vector-borne diseases, characterised by high fever and severe pain in the joints, taking their toll on our lives, experts have listed down some of the misconceptions about them that have been setting off false alarm bells around the country and undermining the efforts to curb and control these ailments.

1. Dengue and chikungunya mosquitoes breed in dirty water: This is the most common misconception associated with dengue and chikungunya. It is not just dirty water that mosquitoes can lay eggs in; clean water that has been stagnant for over five days can also often act as the best breeding ground for Aedes aegypti, the yellow fever mosquito. Discarded tyres and tubes, empty flower pots, water stored in drums and water collected under refrigerators after defrosting can all be potential breeding havens for mosquitoes.

2. Having dengue once means it will not occur again: There are four different types of dengue viruses namely DEN 1, 2, 3 and 4. Being affected by one of the four types offers no protection against other strains, which means much like common flu, dengue can be contracted multiple times by a patient over the course of his/her lifetime.

3. Antibiotics are needed to treat dengue and chikungunya: So far, there is no vaccine that can immunise human beings against these diseases but vaccine for dengue will be coming soon. Nearly 75 percent of dengue cases are curable just by properly dispensing oral fluids and providing proper care and treatment to patients. Only prevention and control of mosquitoes can ensure long-term protection against these diseases.

4. Low platelet count does not always mean dengue: People tend to associate low platelet count with dengue. While it is a good indicator to find out if a patient is suffering from dengue or not, a common cold and viral fever can also bring down your platelet count. There are several other viral infections which can result in a low platelet count; people diagnosed with blood-related diseases, anaemia, severe infections and immunological disorders are bound to have fewer platelets in their blood.

5. Using insecticide sprays is enough to kill mosquitoes: While sprays and fumigation can prove beneficial in curbing the mosquito population to a great extent, using only insecticides cannot ensure 100 percent safety against mosquitoes. The main reason for this is mosquitoes get killed but eggs and larvae don’t get killed. It is equally important to keep your surroundings clean and tidy. Vectors are born in stagnant water accumulated in coolers, air conditioners, pots, ornamental plants, fountains, water tanks, bird feeders, etc. Hence, it is important to maintain hygiene in and around the house, and not allow water to accumulate anywhere.

6. Chikungunya will lead to joint deformity: While symptoms of chikungunya include joint pain and muscle pain, and can closely mimic rheumatoid arthritis or other rheumatologic diseases, the vector-borne disease cannot deform your joints. Most patients recover fully but in some cases, the joint pains may persist for weeks or months.

Given the rapid rise in the number of reported cases of dengue and chikungunya, it is essential for every individual to contribute in the fight against these deadly diseases and to keep India healthy and illness-free. Accurate information, coupled with proper preventative measures, can play a major role in achieving this aim and ensure a tomorrow free from the threat of dengue and chikungunya.

Source: Deccan Chronicle News