Read more: http://www.livestrong.com/article/172469-list-of-emerging-viral-zoonotic-diseases/#ixzz19RI4Tkfl http://www.livestrong.com/article/172469-list-of-emerging-viral-zoonotic-diseases/
UNDIAGNOSED DISEASE - UGANDA (09): YELLOW FEVER VACCINATION
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A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Tue 28 Dec 2010
Source: The New Vision (Uganda) [edited]
Yellow fever: ring vaccination not enough
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At least 2.5 million people will be vaccinated in northern Uganda
against the yellow fever [outbreak] that had by the weekend [25-26
Dec 2010] killed 45 people and infected 178 others.
The disease [yellow fever], whose fatality rate ranges between 15
percent and 50 percent, is taken so seriously that just one confirmed
case is considered an outbreak by the World Health Organisation.
While the health ministry has instituted measures to contain the
disease, a mass rather than ring-vaccination would be a more
effective control mechanism. Diseases know no borders. With increased
travel within the region the disease could have been transmitted far
beyond the surrounding districts. Therefore, a mass vaccination
[campaign], as was done in the Gambia in the 1970s, is the best
approach in the long run. Yellow fever vaccination could also be
added to the expanded programme for immunisation that currently
covers the 6 killer diseases (tetanus, diphtheria, whooping cough,
polio, tuberculosis, and measles).
Global statistics show that yellow fever cases are on the increase
with 90 percent of the 200 000 cases registered annually being in
Africa. Uganda is therefore, likely to experience a resurgence of
yellow fever, just like polio a few years ago.
Since most Ugandan health units are not equipped to test for yellow
fever, the medical workers should be highly suspicious and
investigate all cases with yellow fever symptoms like high fever,
chills, headache, muscle aches, vomiting, and backache. Anybody who
presents [with] these symptoms should immediately take a medical check-up.
Uganda should be more vigilant since all factors responsible for the
resurgence of yellow fever are prevalent here -- reduced immunisation
against the disease; deforestation bringing people in closer contact
with monkeys; and population movements making it easier to transport
the disease far and wide.
Therefore, unless stringent measures like mass immunisation are taken
in collaboration with neighbouring countries, Uganda is likely to
register more yellow fever outbreaks in other places with its attendant costs.
--
Communicated by:
Thomas James Allen
[The following commentary is predicated on the assumption that the
outbreak of undiagnosed disease affecting several villages in
northern Uganda has been unequivocally identified as an outbreak of
yellow fever virus infection. This remains to be confirmed
unequivocally by laboratory testing.
Yellow fever is an acute viral haemorrhagic disease transmitted by
infected mosquitoes. Several different species of the _Aedes_ and
_Haemagogus_ mosquitoes transmit the virus. The mosquitoes either
breed around houses (domestic), in the jungle (wild), or in both
habitats (semi-domestic).
The following information is taken from the WHO fact sheet at
There are 3 types of transmission cycles.
- Sylvatic (or jungle) yellow fever: in tropical rainforests, yellow
fever occurs in monkeys that are infected by wild mosquitoes. The
infected monkeys then pass the virus to other mosquitoes that feed on
them. The infected mosquitoes bite humans entering the forest,
resulting in occasional cases of yellow fever. The majority of
infections occur in young men working in the forest (such as for logging).
- Intermediate yellow fever: in humid or semi-humid parts of Africa,
small-scale epidemics occur. Semi-domestic mosquitoes (that breed in
the wild and around households) infect both monkeys and humans.
Increased contact between people and infected mosquitoes leads to
transmission. Many separate villages in an area can suffer cases
simultaneously. This is the most common type of outbreak in Africa.
An outbreak can become a more severe epidemic if the infection is
carried into an area populated with both domestic mosquitoes and
unvaccinated people.
- Urban yellow fever: large epidemics occur when infected people
introduce the virus into densely populated areas with a high number
of non-immune people and _Aedes_ mosquitoes. Infected mosquitoes
transmit the virus from person to person.
There is no specific treatment for yellow fever, only supportive care
to treat dehydration and fever. Associated bacterial infections can
be treated with antibiotics. Supportive care may improve outcomes for
seriously ill patients, but it is rarely available in poorer areas.
Vaccination is the single most important measure for preventing
yellow fever. In high risk areas where vaccination coverage is low,
prompt recognition and control of outbreaks through immunization is
critical to prevent epidemics.
To prevent outbreaks throughout affected regions, vaccination
coverage must reach at least 60 percent to 80 percent of a population
at risk. Preventive vaccination can be offered through routine infant
immunization and one-time mass campaigns to increase vaccination
coverage in countries at risk. WHO strongly recommends routine yellow
fever vaccination for children in areas at risk for the disease.
The yellow fever vaccine is safe and affordable, providing effective
immunity against yellow fever within one week for 95 percent of those
vaccinated. A single dose provides protection for 30-35 years or
more, and probably for life.
The HealthMap/ProMED-mail interactive map of Uganda can be accessed
at
[see also:
Undiagnosed disease - Uganda (08): yellow fever susp. 20101224.4531
Undiagnosed disease - Uganda (07): plague suspected 20101208.4382
Undiagnosed disease - Uganda (06) 20101206.4365
Undiagnosed disease - Uganda (05) 20101205.4354
Undiagnosed disease - Uganda (04) 20101203.4340
Undiagnosed disease - Uganda (03) 20101202.4334
Undiagnosed disease - Uganda (02): (TG) 20101130.4302
Undiagnosed disease - Uganda: Acholi, RFI 20101129.4297]
...................................cp/mj/mpp
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