includes excessive bleeding at venipuncture sites,
the nose, and gums. Tissue is easily bruised. In
some patients, after a few days of fever, their con-
dition deteriorates into sudden shock (known as
the dengue shock syndrome) with blotchy cool
skin, cyanosis around the mouth, rapid pulse, and
abnormally low blood pressure. In untreated cases
of the dengue shock syndrome, the fatality may
be as high as 40 to 50 percent.
Outbreaks of dengue hemorrhagic fever have
been reported throughout Southeast Asia and
Cuba. The occurrence is during the wet season
when the Aedes aegypti population is highest.
About a third of all deaths are under 15 years of
age. This disease primarily affects the indigenous
The infectious agent is the dengue virus (types
1, 2, 3, and 4). The reservoir is Aedes aegypti mos-
quito and man, and it is transmitted by a mos-
quito bite. The disease is believed to occur by an
immunological reaction from a second or subse-
quent infection with the dengue virus. See the
Dengue Fever section for method of control.
Giardiasis is a parasitic infection of the small
intestine. Symptoms may include chronic diar-
rhea, excess fat in the stools, abdominal cramps,
bloating, frequent loose pale stools, fatigue, and
weight loss. The diagnosis is established by iden-
tification of cysts or trophozoites in feces.
Giardiasis occurs worldwide and in children
more often than in adults. More cases occur in
areas with poor sanitation, in institutions, and in
day-care centers. Waterborne outbreaks have been
frequently seen in the United States.
The infectious agent is Giardia lamblia, a pro-
tozoa. Reservoirs include man, beavers, and other
wild or domestic animals.
Local outbreaks occur when the cysts are in-
gested with contaminated water and less often in
fecally contaminated food. Transmission may oc-
cur from person to person by the fecal-oral route
in day-care centers.
The incubation period ranges from 5 to 25
days. Giardiasis is communicable during the
period of infection; undiagnosed carrier states are
common. Treat the infection as directed by a med-
ical officer. Quinicrine hydrochloride (Atabrine)
or metronidazole (Flagyl) are drugs of choice.
Preventive measures for control include (1)
filtering of public water supplies suspected to be at
risk from human or animal fecal contamination;
(2) ensuring that families, inmates, and personnel
concerned with institutions and day-care centers
receive training in personal hygiene after defeca-
tion; and (3) ensuring that emergency water sup-
plies taken from suspected sources are boiled or
treated with chlorine or iodine.
Management of patients, contacts, and the
nearby environment include (1) enteric precau-
tions for patients and (2) investigating contacts
and the environment for the source of infections.
There is no requirement for quarantine.
Epidemic measures include investigating cases
to determine a common source, such as water,
food, or direct contact, and instituting measures
to prevent transmission.
Several different illnesses are considered as
viral hepatitis; they have similarities and dif-
ferences. This section will discuss the two major
VIRAL HEPATITIS A. The onset is
gradual over several days with symptoms of fever,
malaise, loss of appetite, nausea, abdominal
discomfort, and, a few days later, jaundice. The
course of this disease varies from the commonly
seen mild form (lasting for 1 to 2 weeks) to the
uncommonly seen severe form (lasting several
months). A convalescence of several weeks can
be expected. Complete recovery without sequelae
can be expected. Many cases are mildly symp-
tomatic with no jaundice. Viral hepatitis A oc-
curs worldwide in epidemics and is endemic in
many developing countries. Many outbreaks oc-
cur in institutions, housing areas, and in military
forces, This disease is more common in school-
age children and young adults.
The infectious agent is the hepatitis A virus.
The reservoir is man. The average incubation
period is about 28 to 30 days, but it will range
from 15 to 50 days, depending on the virus dosage
Transmission is from person to person by the
fecal-oral route. Hepatitis A virus is at the highest
levels in feces 1 to 2 weeks before the symptoms
occur and decreases rapidly after the onset of
jaundice. Many outbreaks are spread by food and
water. Raw or under-cooked clams and oysters
have been incriminated. Viral hepatitis A appears
to be most communicable during the 2 weeks
before the symptoms occur and is probably not
transmitted after the first week of illness. There
is no specific treatment, except for supportive