Category: Yellow Fever

Yellow fever epidemic has WHO scrambling

26/8/2016

Mosquito nursery

The World Health Organization is scrambling to deliver enough yellow fever vaccine to cities in central Africa. An epidemic is burning through the populations of non-immune people in the urban centres. The potentially lethal disease is spread by mosquitoes. The Aedes adgypti is the species that is the vector.

Conditions in the rapidly growing urban centres in Africa make for easy mosquito breeding. The close proximity of non-immune people in often poor conditions make for the potential for rapidly spreading epidemics.

The potentially lethal disease is completely preventable with a one-time vaccination. The vaccine has not been a top priority for quite some time. Only four facilities are producing the vaccination and it takes a year and a half to complete the process. Currently about 6 million doses are available world wide.

The outbreak in Kinshasa, DRC, needs 16 million doses to quell the epidemic. The current epidemic started in Angola. The oil exporting country had cut back on public sanitation projects due to the drop in oil revenues which set up a perfect mosquito breeding scenario. Mosquitoes can lay eggs in very small amounts of still water that will hatch into disease carriers.

The disease was initially misdiagnosed as food poisoning which allowed it to spread unchecked. When it was correctly identified, a series of mistakes like improper refrigeration, no syringes to administer the vaccine and what still has the health workers mystified, one million doses gone missing. Because mosquitoes don’t respect political boundaries it has now spread to the centre of the continent.

Kinshasa is trying to cope with the epidemic coupled with lack of vaccine by spraying insecticide over any surfaces that may harbour A. Egypti. They are also doing a garbage sweep to try to reduce the number of breeding sites.

The spread of yellow fever and the apparent fumbling of the initial outbreak has WHO worried. Cases have popped up in Kenya but also in China which houses A. Aegypti. In fact any country that can support that breed of mosquito is vulnerable to the disease if it enters the insect population there.

A aegypti mosquito are now distributed to every continent.

Further reading:
WHO
The Washington Post

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Yellow fever may be the next epidemic

24/5/2016

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US areas with A. aegypti mosquito.

Yellow Fever(YF) has broken out in Angola. The disease is centered in the capital city Luanda with over 24 000 cases as of May 19. There have been 298 deaths due to the disease. While the current outbreak is greatest in Angola, cases have also been confirmed in the Democratic Republic of the Congo.

It is difficult to gauge how many cases of the disease have occurred, with some experts stating that there may be as many as 250 times as many cases as those which are brought to medical personnel.

Any urban outbreak is cause for real concern. WHO convened a special conference to deal with the mounting cases. They have dubbed it a “serious public health event”.

The disease is caused by a virus that is spread when an infected mosquito bites. The two types of mosquitoes that currently spread the disease are found throughout Africa, Americas and much of Asia. In the wild, primates are the reservoir for the virus. When a mosquito bites an infected monkey and goes on to bite a human, the virus is spread. In an urban centre, the virus can spread through mosquito bites to other humans.

YF has been known in New Orleans and Gibralter in the early 1900s but a combination of vaccinations and aggressive mosquito control has kept it at bay. It is firmly established in Venezuela and Brazil.

WHO is particularly concerned about this outbreak because of the potential to cause a serious outbreak in China, home to two billion people. China and Angola have close economic ties based on the oil industry. Some airlines offer direct flights from Luanda to Beijing. As of April 11, the public health authority in the PRC has identified 11 cases of YF in their citizens who have travelled/worked in Angola.

The world maintains a stockpile of vaccine which is effective in preventing YF. Approximately 40 million doses are on hand. In order to stop the human to human transmission of the virus many more doses are needed and the process of manufacturing it takes time.

Travellers to and from Angola may be required to show proof of vaccination in order to prevent the spread of the disease.

Sources:
Science Daily
WHO
CBC News

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Killer yellow fever spreads to DR Congo

13/4/2016

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Tiny and deadly

The worst outbreak in 30 years of yellow fever has hit the African country of Angola. Health care providers are attempting to head off the spread of this mosquito borne disease with a vaccination programme. They have vaccinated millions of Angolans but have many more to go and are rapidly depleting the stocks of vaccine.

Prevention is the key to calming the latest epidemic. There is no cure once the virus takes hold of a person. Most people have flu like symptoms but about 15% go on to experience the severe form of the disease. Of those so stricken, half will die. As the disease progresses, it becomes a haemorrhagic fever and people bleed out.

The flare up of the disease started in Luanda in mid-February and quickly escalated to 1600 confirmed cases. Two hundred twenty-five have died.

Now the disease is moving into the DR Congo. There are a reported 21 fatalities to date with 151 confirmed cases. Some of those cases have been traced to the outbreak in Angola. The countries share a border.

Currently, yellow fever is endemic in 44 countries. Africa and Latin America are the most strongly hit. WHO estimates that 60 000 people die from the disease each year.

Those people who are planning travel to areas affected by this haemorrhagic disease are strongly urged to obtain a vaccination against the virus.

Yellow fever is only one of a large number of haemorrhagic fevers that are largely confined to tropical areas. Mosquitoes are one of the insects that spread the viruses, but other biting insects are known to spread these diseases as well. More than 100 diseases are spread by arthropods. While most of these diseases are believed to have originated in tropical areas, they don’t always stay there. A combination of warming climate and quick travel can spread blood infections to new areas.

An example of a recent introduction to N. America is the West Nile Virus. About 15 years ago a few cases were detected on the eastern US. Both people and horses were infected. Some infections spread by mosquito bites were mild but others led to complications and deaths. The disease now is established in most of the continent.

Sources:
CBC News
WHO
Microbiology and Immunology on-line

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Yellow fever epidemic has WHO scrambling

Yellow fever may be the next epidemic

Killer yellow fever spreads to DR Congo

Barbara McPherson

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