Other Infectious Diseases
In
some countries, USAID supports efforts to address
other infectious diseases, such as dengue,
onchocerciasis, meningitis, yellow fever, and
chagas. This support is only carried out if
a disease presents a major public health
threat in that country or region and if there
is a clear role for USAID. In addition to supporting
specific disease control efforts in particular
countries when required, USAID also investigates
other broader issues, such as the impact of
nutrition and of micronutrient interventions
on the control and prevention of infectious
diseases.
Other infectious diseases
receiving USAID support:
Dengue
Amid growing concerns over the increasing
spread and incidence of dengue and dengue hemorrhagic
fever (DHF), the World Health Assembly passed
Resolution 46.31 in 1993. The Resolution urged
affected Member States to strengthen their programs
of prevention and control and requested that the Director-General
establish containment strategies. In the absence
of a dengue vaccine, vector control presently
remains the only option available for disease
prevention and control. In 1995, a World Health Organization (WHO) consultation
enunciated the global strategy, comprising five
major components: (i) selective integrated vector
control, with community and intersectoral participation;
(ii) active disease surveillance based on a strong
health information system; (iii) emergency preparedness,
(iv) capacity building and training; and (v)
vector control research. Strategies have also
been developed in each of the most severely affected
WHO regions, i.e., South-East Asia (SEARO), The
Western Pacific (WPRO), and The Americas (AMR), and they
form the bases for national program
planning.
Despite these national and
international efforts, the increasing epidemiological
trend has not been reversed and operational “success
stories” are few. There are currently an
estimated 50 million cases of dengue annually,
including 400,000 cases of DHF and dengue shock
syndrome. Only a small proportion of cases are
officially reported, but 1998 witnessed unprecedented
levels of reporting, with approximately 1.2 million
cases reported to WHO from 56 countries. USAID
is working to control and eradicate dengue in
the following countries: Cambodia, Dominican
Republic, El Salvador, Honduras, Nicaragua, Peru,
and the Philippines.
Japanese
Encephalitis
Japanese encephalitis
(JE) is a viral illness caused by a flavivirus
that is transmitted by Culicine mosquitoes. Domestic
pigs are among the most important amplifying
hosts of JE virus. In the absence of pigs, cattle
and wading birds “host” the virus for
multiplication. Children are at a greater risk
of being infected by the JE virus. Incidence
of JE is increasing in some regions, while it
is declining in others. This could be largely
attributed to the changing weather, vector composition,
vector host preference, available vertebrate
hosts and human factors, such as farming, irrigation
practices, and population movement.
JE is transmitted seasonally.
In some tropical and subtropical areas, the incidence
peaks during and shortly after the raining season.
But transmission may occur even during the dry
season in regions where mosquitoes breed throughout
the year. Clinical manifestation
of JE varies. More than 90 percent of infected persons
are asymptomatic. Symptomatic infections can
range from aseptic meningitis to severe infection
that results in 30 percent fatality rate. The illness
may progress from high fever, chills, headaches,
and gastrointestinal ailments to infection of
the nervous system, leading to neurologic sequelae
and death.
Kala-azar
(Leishmaniasis)
Kala-azar, also known as visceral leishmaniasis, tropical splenomegaly,
sirkari disease, and dumdum or Assam fever, is reported to affect 500,000
people worldwide every year. It is caused by the protozoan Leishmania
donovani, which is transmitted to humans through infected female phlebotomine
sandfly bites. Ninety percent of visceral leishmaniasis cases are found
in Bangladesh, Brazil, India, Nepal, and Sudan. It is believed that the
number of leishmaniasis cases is increasing partly due to population
movement and ecological changes that increase human exposure to the sandfly
vector.
Classic Kala-azar, which is
progressive and fatal if not treated, is an insidious,
chronic disease that is characterized by irregular
fever, anorexia, weight loss, cough, gross enlargement
of the spleen and liver, mild anemia, and emaciation.
This may be preceded by rigor and vomiting. If
untreated, Kala-azar, which is the most severe
form of leishmaniasis, has a mortality rate of
nearly 100 percent.
For more information on other
infectious diseases, visit:
- U.S. Centers
for Disease Control and Prevention (CDC)
- Institute
of Medicine's Forum on Emerging Infections
USAID is a proud supporter of the Institute of Medicine’s Forum on
Emerging Infections. Sessions of the Forum examine emerging and long-standing
problems in light of the most recent advances that may lead to further
innovation or resolution. In recent years, such dialogue has led to
the establishment of priority issues for infectious disease research
and public health policy, the identification of issues for further
investigation, and opportunities for more effective collaboration between
the private and public sectors. The Forum’s workshop reports have
informed policymakers, documented innovative ideas, and brought attention
to some of the most important infectious disease issues of the last
decade.
- WHO
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