Brazil’s Yellow Fever outbreak: Medical stuff we should know, from NAIAD

March 9, 2017

Accurate information can be the greatest tool in the fight against diseases, infectious or vector-borne. NAIAD slide.

Accurate information can be the greatest tool in the fight against diseases, infectious or vector-borne. NAIAD slide.

Brazil endures an outbreak of Yellow Fever in early 2017. Mosquitoes transmit Yellow Fever from one mammal host to another. Famously, Yellow Fever had to be controlled to allow construction of the Panama Canal between 1910 and 1915.

It should be just a matter of days, or perhaps a few hours, before harpies on the right and in anti-science trenches demand “return” of DDT to fight this outbreak, arguing that EPA didn’t know what it was doing when it banned DDT from farm use, and probably dropping cheap shots at Rachel Carson and “environmentalists.”

Yellow Fever is usually carried by mosquitoes in the species Aedes aegypti, a nasty little bug that carries several diseases to humans including Zika virus and West Nile virus.

Distribution of Aedes aegypti mosquitoes in the U.S. Map by U.S. CDC, via Wikipedia

Distribution of Aedes aegypti mosquitoes in the U.S. Map by U.S. CDC, via Wikipedia

Astute observers know that A. aegypti are almost ubiquitous in warmer human cities, so the transmission of the disease requires only that a host (usually human) shows up infected with the pathogen, and an epidemic might occur.

Those observers also know that all mosquitoes are resistant or immune to DDT and frequently to other pesticides as well, their having been bombarded with pesticides for 60 or more years, and consequently having evolved resistance alleles. So spraying with DDT won’t work.

That’ won’t stop those who relish slandering Carson or who wish to impugn the humanity and good motives of environmentalists.

Get facts, first.

Come Dr. Anthony Fauci and Dr. Cahtharine Paules of the U.S.’s National Institute of Allergy and Infectious Diseases (NAIAD), part of the National Institutes of Health (NIH) to offer information to calm the hyperventilated, and to inform the serious and concerned citizen with an article in the New England Journal of Medicine, explaining Brazil’s problem, Yellow Fever, and what U.S. residents need to do, and this press release from NAIAD to get the key points across quickly.

Will anyone listen?

Yellow Fever in the Americas

Current Outbreak Merits Close Watch
March 8, 2017

The unusually large outbreak of yellow fever now occurring in rural Brazil deserves careful attention by world health authorities, notes Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health. Writing in a Perspectives piece for the New England Journal of Medicine, Dr. Fauci and his associate Catharine I. Paules, M.D., note that this latest outbreak of a serious mosquito-borne virus comes as Zika virus, which is spread by the same mosquito as yellow fever virus, continues to affect countries throughout the Americas.

Historically, yellow fever has claimed millions of lives, including many thousands in the United States. The Philadelphia epidemic of 1793, for example, killed approximately ten percent of the city’s population. In its most serious form, yellow fever symptoms include high fever, hemorrhagic manifestations, kidney failure, liver malfunction and jaundice (yellowish appearance of the eyes and skin, which gives the disease its name.)

A vaccine has been available since 1937 and confers lifelong immunity in up to 99 percent of those who receive it. Extensive immunization campaigns, along with effective mosquito control—especially in developed countries—have reduced yellow fever cases worldwide. Nevertheless, localized outbreaks in parts of Africa and Central and South America account for an estimated 84,000 to 170,000 severe cases of disease and between 29,000 and 60,000 deaths annually.

The Brazilian outbreak is a manifestation of the “sylvatic,” or jungle, transmission cycle in which forest-dwelling mosquitoes spread the virus primarily to non-human primates, with humans serving only as incidental hosts. At this time, there is no evidence that the outbreak is transforming into its “urban” cycle, but authorities should remain alert for this possibility, the authors note. In the urban cycle, yellow fever virus is usually spread by city-dwelling Aedes aegypti mosquitoes directly to people. An urban cycle of yellow fever in Angola and the Democratic Republic of Congo that began in late 2015 caused 961 confirmed cases and 137 deaths. During that outbreak, write Drs. Fauci and Paules, the world’s emergency vaccine stockpile reserve was exhausted, limiting the number of available vaccine doses and making the outbreak more difficult to control. To prevent a similar occurrence during a future yellow fever outbreak in Brazil or elsewhere, “early identification of cases and rapid implementation of public health management and prevention strategies, such as mosquito control and appropriate vaccination, are critical,” they write.

In an era of frequent international travel, an increase in domestic cases in Brazil has the potential to spread yellow fever to non-endemic areas and could pose serious disease-control challenges, Drs. Fauci and Paules observe. They urge clinicians, especially those in the United States and other places where yellow fever is uncommon, to inform themselves about yellow fever symptoms and to adopt a high index of suspicion for this diagnosis, particularly when examining travelers returning from affected regions.

ARTICLE:
CI Paules and AS Fauci. Yellow fever: Once again on the radar screen in the Americas. New England Journal of Medicine DOI: 10.1056/NEJMp1702172 (2017).

WHO:
Dr. Fauci is available to discuss this article.

CONTACT:
To schedule interviews, please contact Anne A. Oplinger, (301) 402-1663, aoplinger@niaid.nih.gov.

Map of Brazil showing confirmed cases of Yellow Fever

Map of Brazil showing confirmed cases of Yellow Fever “in the current outbreak,” as of March 2017. Information from Brazil’s Ministry of Health. NEJM image.


DDT FAIL: Mosquito-borne diseases deplete medical care in DDT’s world capital

September 15, 2016

India News Today photo shows insecticide fogging in crowded Delhi neighborhoods to combat Chikungunya virus by striking down mosquitoes that transmit the disease from one human to another.

India News Today photo shows insecticide fogging in crowded Delhi neighborhoods to combat Chikungunya virus by striking down mosquitoes that transmit the disease from one human to another.

In the western world, libertarians, so-called conservatives and anti-science people call for a “return” of DDT to fight Zika virus spread.

But in the world’s DDT capital, India, where DDT is still made and more DDT is applied than in the rest of the world combined, DDT’s failures stand out. News reports say health care in key Indian cities is hamstrung by doctors and nurses getting mosquito-borne diseases.

Why don’t they just use “the magic powder,” DDT, to wipe out mosquitoes? Oh, Dear Reader, India has used DDT extensively, for everything, for 60 years. Mosquitoes that carry disease, and all other mosquitoes, and many other insect pests, developed resistance and immunity to DDT from that use.

Apart from the fact that DDT would be the WRONG pesticide to use for anything other than malaria-carrying mosquitoes from the genus Anopheles, it simply does not work.

If DDT advocates paid attention to news and history, they’d not call for more DDT anywhere for any reason.

India Today detailed the simmering crisis in Delhi in a story headlined, “Dengue-chinkungunya outbreak takes down doctor, nurses and sanitation workers”:

Subhead:

Apart from doctors, even nurses, other members of the medical staff and sanitation workers are going on leave at a time when the number of people afflicted by dengue and chikungunya this year in the city and its suburbs has crossed two thousand.

As outcry over an onslaught of viral diseases in the Capital reaches fever pitch and hospitals struggle in the face of an unrelenting tide of patients, the men in white too have started calling in sick.

Apart from doctors, even nurses, other members of the medical staff and sanitation workers are going on leave at a time when the number of people afflicted by dengue and chikungunya this year in the city and its suburbs has crossed two thousand.

Malaria is carried almost always by Anopheles, but chikungunya is carried by two species of Aedes, Aedes aegypti and Aedes albopictus. These mosquitoes also carry dengue fever and Yellow fever. A. aegypti is the principal carrier of the Zika virus, worldwide. Health workers being felled by dengue and chikungunya tells us the area would also be fertile territory for the spread of Zika virus, if it were introduced there.

Careful watchers, therefore, will understand that DDT has worn out its usefulness against a wide variety of mosquito-borne diseases including Zika.

“In our hospital, 10 per cent of the staff is currently down with fever,” said Dr Ramesh Chugh, medical superintendent of Pt Madan Mohan Malaviya Hospital in south Delhi. “We have over 100 doctors, and currently 7-8 doctors are down with fever.”

Experts say heavier than usual rainfall, a large number of construction projects and scores of open drains in Delhi are allowing mosquitoes to breed in stagnant water.

Far too many commenters fail to understand that DDT was never the chief tool in fighting malaria, or any other disease. Instead, DDT was used to knock down local populations of mosquitoes, temporarily, so health care and better housing and other measures could cure humans of the diseases and remove mosquito breeding areas from areas around human homes and human activities. India’s failure to provide good sewage drainage, good storm sewage drainage, and otherwise plug up potholes and even tiny water catching places allows mosquitoes almost free rein. India relied too long on poisoning everything with DDT, instead of building a mosquito-resistant urban area.

At Lok Nayak Hospital in central Delhi, 18 doctors are on leave. “Either the doctors are down with fever or somebody in their family is ill. The doctors are taking leave for at least 4-5 days. We have had cases where physicians were ill but returned to work early seeing the number of patients,” said a senior doctor.

NURSES AND SANITATION WORKERS ALSO ON LEAVE

In east Delhi’s Lal Bahadur Shastri Hospital, 18 members of the medical staff, including doctors, nurses and sanitation workers, are absent. “In a staff of nearly 1200, 10-15 doctors are on leave due to viral illnesses,” said Dr Punita Mahajan, medical superintendent of Baba Ambedkar Hospital in northwest Delhi. “We are not exerting pressure on the doctors to continue if they feel slightly unwell as it is very important for the hospital to ensure that they remain healthy.”

The Delhi government has asked hospitals to ensure that dengue and chikungunya patients are treated without distress.

Officials say the health department has already dedicated an additional 1,000 beds for those suffering from fever at the Rajiv Gandhi Super Speciality Hospital, Janakpuri Super Speciality Hospital and Deep Chand Bandhu Hospital.

These institutes have been designated nodal hospitals for fever in the city. All hospitals- government and private – in the National Capital Territory have been directed to increase their surge capacity.

“While doctors are trying their best to remain on duty till the effect of vector-borne diseases recedes the city, the shortage in staff and the new directions from the government would add to the existing burden,” said a doctor on condition of anonymity.

The Delhi government says it is fully prepared to battle with the onslaught of diseases and has denied in the city high court claims that the Capital is facing its worst dengue crisis.

In an affidavit filed in the court, it said strict surveillance of preparedness and impact of these diseases has been carried out for taking further preventive measures as, due to environmental conditions, the number of diseases such as dengue, chikungunya and malaria shows an upswing during July to October.

India continues to learn that DDT is not magic, not often useful, and sometimes detrimental to disease control efforts.

Will the rest of the world watch and learn? No, DDT will not and cannot help in the fight against Zika virus’s spread to humans. Waste no more time wondering, but get on with the hard work of draining mosquito breeding places, improving houses with window screens and other improvements, and developing vaccines and other medicines. Now.

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