YELLOW FEVER

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YELLOW FEVER
Dr.I.Selvaraj,I.R.M.S B.SC.,M.B.B.S.,(M.D
Community medicine).,D.P.H.,D.I.H.,P.G.C.HFW(NIHF
W,New delhi) Sr.D.M.O(ON STUDY LEAVE) INDIAN
RAILWAYS MEDICAL SERVICE
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In 1881, Carlos Juan Finlay, a physician in
Havana, first proposed that yellow fever was a
mosquito-borne illness, which subsequently was
proven by Walter Reed and colleagues.
U.S. Army doctor Discovered the Cause of Yellow
Fever August 27, 1900
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Research and Walter Reed Walter Reed, M.D.,
(1851-1902) was an American Army surgeon who led
the team which proved the theory first set forth
in 1881 by the Cuban doctor and scientist Dr.
Carlos Finlay that yellow fever is transmitted by
mosquitoes rather than direct contact. The risky
but fruitful research work was done with human
volunteers, including some of the medical
personnel such as Clara Maass and surgeon Jesse
W. Lazear Walter Reed Medal winner who allowed
themselves to be deliberately infected and died
of the virus. All this lead to the elimination of
Yellow Fever from Cuba and allowed the final
construction of the Panama Canal.
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Clara Maass
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On August 14, 1901, Maass allowed herself to be
bitten by infected mosquitoes for the seventh
time. Maass once again became ill with yellow
fever on August 18 and died on August 24. Her
death roused public sentiment and put an end to
yellow fever experiments on humans.
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• Thirty-three countries, with a combined
  population of 508 million, are at risk in Africa.
  These lie within a band from 15N to 10S of the
  equator.
• In the Americas, yellow fever is endemic in nine
  South American countries and in several Caribbean
  islands. Bolivia, Brazil, Colombia, Ecuador and
  Peru are considered at greatest risk.
• There are 200,000 estimated cases of yellow fever
  (with 30,000 deaths) per year.

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Countries regarded as yellow fever infected
Africa  Angola, Benin, Burkina Faso, Burundi,
Cameroon, Central African Republic, Chad, Congo,
Democratic Republic of Congo (Zaire), Equatorial
Guinea, Ethiopia, Gabon, Gambia, Ghana, Guinea,
Guinea-Bissau, Ivory Coast (Cote D'Ivoire),
Kenya, Liberia, Mali, Niger, Nigeria, Rwanda, Sao
Tome and Principe, Senegal, Sierra Leone,
Somalia, Sudan (South of 15 N), Togo, Uganda,
Tanzania, Zambia.
America  Bolivia, Brazil, Colombia, Ecuador,
French Guiana, Guyana, Peru, Suriname, Trinidad
and Tobago, Venezuela, Panama.
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• As of 6 December 2005, the Federal Ministry of
  Health,SUDAN reported to WHO a total of 565
  cases, including 143 deaths, with a case fatality
  rate of 25.3.
• As of 19 December2005, the Ministry of Health,
  Guinea has reported a total of 114 suspected
  cases of yellow fever with 26 deaths,
  Twenty-three of these cases have been laboratory
  confirmed.

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There are no reported cases of yellow fever in
Asia. It is suspected that the high incidence of
dengue fever helps confer protection against
yellow fever, and that the Asian mosquito strains
are not as competent as vectors of the disease.
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• AGENT
• Genus Flavivirus fibricus,
• Group B Arbovirus
• Family Toga virus
• The yellow fever virus is 35-40 nm in
• size. It consists of a single strand of RNA virus

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The photomicrograph shows multiple virions of the
yellow fever virus at a magnification of 234,000x
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VECTORS

• Aedes mosquitoes, including
• A. aegypti,
• A. africanus,
• A. simpsoni,
• furcifer,
• luteocephalus,
• and A. albopictus (Asian tiger mosquito).
•  Urban yellow fever is transmitted by the Aedes
  aegypti mosquito.    Jungle, or sylvatic, yellow
  fever is transmitted by Haemagogus and other
  mosquitoes (such as Masoni africana) of the
  forest canopy (tree-hole breeding mosquitoes).  

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• Reservoir Monkey, Human, Mosquito
• Incubation period Intrinsic IP3to 6 Days
• Extrinsic IP
  1to 2 weeks
• .Period of communicability First 4 days of
  illness
• Mode of Transmission 1.Sylvan cycle
• 2. Urban
  cycle

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Race No known racial predilection exists. Sex
Both sexes are infected equally Age All ages are
suceptible to yellow fever. Jungle yellow fever
primarily affects nonimmunized adults who work
as foresters,wood cutters hunters in endemic
areas and persons residing on the edge of the
jungle. Infants born of immune mothers have
antibodies up to 6 months of life
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ENVIRONMENTAL FACTORS

• TROPICAL CLIMATE
• HUMIDITY (60)
• TEMPERATURE ( 24ºC)
• SOCIAL FACTORS URBANISATION , TRAVEL EXCESSIVE
  RAINS

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• The natural host for the yellow fever virus in
  forest areas is non-human primates (usually
  monkeys and chimpanzees).
• The vectors of yellow fever in forest areas in
  Africa are Aedes africanus . In South America,
  the primary vector is the Haemagogus species.
• In urban areas of both Africa and South America,
  the vector is Aedes aegypti.

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The natural yellow-fever cycle is
mosquito-monkey-mosquito.  The shift from jungle
yellow fever to urban yellow fever is thought to
be the result of humans entering the sylvan
setting and becoming part of the yellow-fever
cycle  Initially, wood cutters and other forest
workers were bitten by forest-canopy mosquitoes
carrying the yellow-fever virus.  The humans then
returned to the urban settings.  
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Clinical features of yellow fever Yellow fever
presents with a variety of clinical signs and
outcomes ranging from mild to severe and fatal
cases. Yellow fever in human beings has the
following characteristics An acute phase
lasting for four to five days and presenting
with - a sudden onset of fever - headache or
backache - muscle pain - nausea - vomiting - red
eyes (infected conjunctiva).
The diagnosis can be strongly suspected when
Faget's sign is present. Faget's sign The
simultaneous occurrence of a high fever with a
slowed heart rate.
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This phase of yellow fever can be confused with
other diseases that also present with fever,
headache, nausea and vomiting because jaundice
may not be present in less severe (or mild) cases
of yellow fever. The less severe cases are often
non-fatal. A temporary period of remission
follows the acute phase in 5 to 20 of cases.
The period of remission lasts for up to 24 hours.
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A toxic phase can follow the period of remission
and presents with - jaundice - dark urine -
reduced amounts of urine production - bleeding
from the gums, nose or in the stool - vomiting
blood - hiccups - diarrhoea - slow pulse in
relation to fever
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No specific treatment is available for yellow
fever. In the toxic phase, supportive treatment
includes therapies for treating dehydration and
fever. In severe cases, death can occur between
the seventh and tenth days after onset of the
first symptoms.
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CONTROL OF YELLOW FEVER
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Theiler won Nobel Prize in 1951 for his
accomplishments
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YELLOW FEVER VACCINE

• The virus first isolated in 1927 by inoculating
  rhesus monkeys with the blood of an African
  patient (Asibi).
• Edward Hindle developed inactivated vaccine
  1928.Theilar and Smith developed 17D vaccine from
  the Asibi strain in cell cultures from
  embryonated chicken eggs.
• It is a safe effective vaccine.

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• Yellow Fever Vaccine, Live (17D Strain Live,
  Freeze Dried).Each 0,5 mL contains Yellow Fever
  Virus 104.1 pfu.
• Vaccine must be maintained continuously at
  temperatures between 5 and -30C
• The vial of diluent should not be allowed to
  freeze.
• The reconstituted vaccine must be kept cool and
  used within 60 minutes following reconstitution.
• The product appears slightly opalescent and light
  orange in color after reconstitution.
• Vials of 5 doses with vials of diluent.
• Reconstitute the vaccine using only the diluent
  supplied (Sodium Chloride Injection).
• Slowly inject the diluent into the vial
  containing the vaccine, let stand for one or two
  minutes and then carefully swirl mixture until a
  uniform suspension is achieved. Avoid vigorous
  shaking as this tends to cause foaming of the
  suspension.
• Administer the vaccine subcutaneously.

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• The yellow fever vaccine has a long record
  of safety, but clinicians should be aware of two
  severe complications from the vaccine.
• Yellow fever-associated neurotropic disease
  (previously known as post vaccine encephalitis),
  occurs 721 days after vaccination. Of the 1/8
  000 000 people who contract this disease, full
  recovery is typical.
• Yellow fever-associated viscerotropic disease
  occurs 25 days after vaccination. It is
  characterized by fever, myalgia, arthralgia,
  increased liver enzymes and bilirubin,
  lymphopenia, thrombocytopenia, disseminated
  intravascular coagulation, hypotension, oliguria
  and rhabdomyolysis. There have been 13 cases
  reported out of over 100 million doses
  administered worldwide.

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• Persons exempted from production of vaccination
• 1.Infants below the age of six months.
• 2. Crew and passengers of an aircraft
  transiting through an airport located in yellow
  fever infected area provided the Health Officer
  is satisfied that such persons remained within
  the airport premises during the period of stay.

• The validity period of international certificate
  of vaccination or re-vaccination against yellow
  fever is 10 years, beginning 10 days after
  vaccination.

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REFERENCE CENTRES INDIA

• 1. National Institute of Virology, Pune
• 2. Central Research Institute, Kasauli

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Aedes aegypti index

• It is a house index.It is defined as the
  percentage of houses and their premises showing
  actual breeding of Aedes aegypti larvae. This
  index should not be more than 1 in airports and
  seaports in endemic areas at least 400 meters
  around their perimeters to ensure freedom from
  yellow fever

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MosquiTRAP. is a novel, simple, easy, low cost,
and efficient trap especially developed to catch
Aedes mosquitoes. MosquiTRAP. allows the
identification of the mosquito species in the
field, thus saving time and avoiding laboratory
routine such as counting eggs and larval
identification. Trapped mosquitoes can also be
used for virus diagnosis. New entomological
indices are (a) the Positive MosquiTRAP
Index (PMI), the percentage of positive traps,
and (b) the Adult Density Index for A. aegypti
and for A. albopictus. Field data can be
collected using hand-held PDAs and then loaded
directly into a Geographical Information System
(GIS), for an efficient determination of local
entomological indices.
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YELLOW FEVER RECEPTIVE AREA

• An area in which yellow fever does not exist, but
  where conditions would permit its development if
  introduced

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• The population of India is unvaccinated
• The vector Aedes aegypti is found in abundance
• The climactic conditions are favourable for its
  transmission
• The common monkey of India is more susceptible
  for yellow fever
• The missing link is in the chain of transmission
  is the virus of yellow fever

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INTERNATIONAL MEASURES
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• A valid international certificate of vaccination
• Aerosol spraying of prescribed insecticides on
  the arrival of aircrafts and ships from endemic
  areas
• Airports and seaports are kept free from the
  breeding of insect vectors at least 400 meters
  around their perimeters
• Clinical surveillance, entomological
  surveillance, epidemiological surveillance

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• A) For entry into India- Any person, Foreigner
  or Indian, (excluding infants below six months)
  arriving by air or sea without a vaccination
  certificate of yellow fever will be kept in
  quarantine isolation for a period up to 6 days
  if
• He arrives in India within 6 days of departure
  from an infected area.
• Has come on a ship which has started from or
  transited at any port in a yellow fever affected
  country within 30 days of its arrival in India
  provided such ship has not been disinfected in
  accordance with the procedure laid down by WHO.
• (B) For leaving IndiaThere is no health check
  requirement by Indian Government on passengers
  leaving India.
• The Government of Guyana requires that all
  persons including diplomats traveling to that
  country from India to possess valid yellow fever
  and cholera inoculation certificates before they
  leave India.

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• GUIDELINES FOR YELLOW FEVER SURVEILLANCE
• Make sure that personnel at health
  facilities in the district know how to identify
  suspected cases of yellow fever.
• Make sure that health facilities use a standard
  case definition to report suspected cases of
  yellow fever.
• Assist health facilities with investigation of
  suspected cases.
• Collect samples for diagnostic testing and
  laboratory confirmation. If necessary, transport
  samples to a drop-off point or specified
  laboratory.
• Notify the national level about the suspected
  case. Alert other health facilities in nearby
  areas about the potential for additional cases.

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• Receive and report laboratory results about
  confirmed cases.
• Coordinate the response to the confirmed case
  with a district emergency response committee.
• Carry out intensified surveillance activities to
  identify additional cases in areas where the
  patient lived, worked or travelled. Collect
  diagnostic specimens from any new suspected
  cases.

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• Monitor and supervise routine disease
  surveillance activities. Analyse data for trends
  suggesting a yellow fever outbreak. Report data
  from routine activities to the national level on
  time.
• Assist and support health facilities with the
  integration of yellow fever vaccine into the
  routine childhood immunization schedule. Make
  sure vaccine and immunization supplies are
  available for routine yellow fever activities.

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• Ref Monitoring the mosquito Aedes aegypti A
  novel surveillance method and newentomological
  indices using the gravid trap MosquiTRAP. and a
  synthetic oviposition attractant (AtrAedes.)
• Ref Aedes aegypti survey of Chennai
  Port/Airport, India
• PREVENTIVE SOCIAL MEDICINE 18th edition
• TEXT OF COMMUNITY MEDICINE T. BHASKAR RAO
• Mansons tropical disease 21st edition
• http//www.who.int/vaccines-documents/DocsPDF/www9
  834.pdf

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