In September and October 1981, an outbreak of conjunctivitis
involving primarily grade-school-aged children occurred in
southeastern Georgia. Between September 5 and October 16, the
Office
of Epidemiology, Georgia Department of Human Resources, received
both
passive and active surveillance reports of over 2,000
conjunctivitis
cases in 20 counties. Reports suggested that the outbreak peaked
in
the week ending September 19. The patients' ages ranged from 6
months
to 84 years (median age = 7 years).
Between September 24 and October 4, a telephone survey of
households with children in three randomly selected first grade
classes (the age group most affected) was conducted in one
community.
Of the 72 selected households, 44 (61%) were contacted. Twenty-two
of
44 (50%) reported one or more persons with conjunctivitis since
September 1. Eighteen of 44 first graders (41%) had
conjunctivitis.
There was no difference in attack rates between males and females,
blacks and whites, and residents within and beyond city limits.
Symptoms reported from the index case in affected households were:
conjunctival injection (86%), lid swelling (73%), watering (73%),
purulent drainage (73%), eye pain (60%), itching (55%), headache
(36%), and discomfort on exposure to bright light (32%). Fever, as
well as respiratory and gastrointestinal symptoms were present in
10%
of cases. Thirty-eight percent of cases involved one eye; 62% were
bilateral. The median duration of illness was 6.5 days (range 2
days-2-1/2 weeks). In nine of the 22 case households (41%), more
than
one person was affected. In three households, multiple cases
appeared
simultaneously. In households with multiple cases, age-specific
attack rates were: less than or equal to 4 years, four of five
(80%); 5-9 years, 29 of 35 (83%); 10-14, six of 14 (43%); 15-19,
zero
of nine; 20-29, one of 11 (9%); greater than or equal to 30, zero
of
31.
Microscopic examination of purulent material obtained from the
eyes of eight acutely ill children in one community revealed small,
pleomorphic intracellular gram-negative rods morphologically
compatible with the presence of Haemophilus organisms. A possible
Haemophilus species was isolated from seven of the eight specimens
but
could not be further identified. A similar organism was isolated
from
17 persons with conjunctivitis in another community. Viral
cultures
from nine patients were negative.
Health authorities considered the possibility that gnats
(Hippelates pusio) were responsible for mechanical transmission of
this disease. These insects derive nourishment from eye secretions
and were unusually prevalent during the outbreak period. Attempts
to
isolate Haemophilis from gnats trapped in a first-grade classroom
were
unsuccessful.
Reported by R Poblete, MD, Baxley, DC Schwekendiek, Tift General
Hospital, Tifton, I Eunice, RN, C Matthews, JT Holloway, MD, Health
District 9, Unit 2, Waycross, J Franklin, Bacteriology Laboratory,
RK
Sikes, DVM, State Epidemiologist, Georgia Dept of Human Resources;
Field Svcs Div, Epidemiology Program Office, CDC.
Editorial Note
Editorial Note: Outbreaks of seasonal conjunctivitis in the
southern
states and southern California were described as early as 1929
(1-5);
they occurred during the summer or early fall and primarily
affected
young children. The etiologic agent was Haemophilus aegyptius
(known
as the Kochs-Weeks bacillus and now as H. influenza biotype III),
and
mechanical vector transmission by gnats has long been suggested.
In
many areas of the southern United States, these insects are
prevalent
during the warm months. Gnat-borne transmission has been
documented
in animal studies (6).
In this outbreak, transmission by gnats was suggested. It was
hypothesized that such transmission may have been facilitated when
children congregated in school yards. It was not possible,
however,
to discern the relative importance of vector or direct
person-to-person spread.
References
Bengston IA. Seasonal acute conjunctivitis occurring in the
Southern states. Public Health Rep 1933;48:917-26.
Davis DJ, Pittman M. Acute conjunctivitis caused by
hemophilus.
Am J Dis Child 1950;79:211-22.
The California eye gnat. Science 1929;69:14.
Dawson CR. Epidemic Koch-Weeks conjunctivitis and trachoma in
the
Coachella Valley of California. Am J Ophthalmol 1960;49:801-8.
Dow RP, Hines VD. Conjunctivitis in Southwest Georgia. Public
Health Rep 1957;72:441-8.
Payne WJ Jr, Cole JR Jr, Snoddy EL, Seibold HR. The eye gnat
Hippelates pusio as a vector of bacterial conjunctivitis using
rabbits as an animal model. J Med Entomol 1977;13:599-603.
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