International Notes
Acute Hemorrhagic Conjunctivitis -- Mexico
In September 1987, an outbreak of conjunctivitis occurred among
residents of several towns in the Yucatan Peninsula of Mexico
(Figure
1). Illness was characterized by conjunctival injection, palpebral
edema, lacrimation, and foreign-body sensation. Subconjunctival
hemorrhages were observed less frequently than expected, occurring
in
13% of patients. The Mexico Field Epidemiology Training Program
surveyed a 10-block area of Cozumel, a resort island reporting many
cases, and found an overall attack rate of 25% among local
residents.
The secondary attack rate among family members of affected
households
was 37%. Cultures of conjunctival swabs obtained from eight of 13
patients were positive for coxsackie virus A24 variant (CA24v).
In July 1988, a second outbreak of conjunctivitis occurred in
Delicias
in the state of Oaxaca in south central Mexico. CA24v was isolated
from
eight of 16 affected persons. In October 1988, a third outbreak was
reported in Tampico, a town in northern Mexico along the gulf coast
and
about 250 miles south of Brownsville, Texas. Three of nine
specimens
from this outbreak sent to CDC for virus isolation were positive
for
CA24v. In all three outbreaks, attack rates appeared to be highest
among school-aged children (i.e., 5-14 years of age).
The outbreak in Mexico subsided during the winter. The Texas
Department of Health was notified of the outbreak and increased its
surveillance for conjunctivitis in the Brownsville area. No cases
in
Texas have been reported.
Reported by: M Gonzalez, MD, F Meneses, MD, L Camacho, MD, A
Moreno,
DD, C Ruiz, MD, Field Epidemiology Training Program, General
Directorate of Epidemiology, Secretariat of Health, Mexico. Div of
Global EIS, International Health Program Office; Respiratory and
Enterovirus Br and Epidemiology Office, Div of Viral Diseases,
Center
for Infectious Diseases, CDC.
Editorial Note
Editorial Note: Acute hemorrhagic conjunctivitis (AHC) is a
clinical
entity characterized by the rapid onset of conjunctival injection,
lacrimation, foreign-body sensation, and in many cases,
subconjunctival
hemorrhages. The illness is caused by enterovirus 70, CA24v, or
adenovirus 11. Epidemiologically, AHC is characterized by its high
communicability; the incubation period is short (24-48 hours),
secondary attack rates in households are high, and transmission is
enhanced by crowding and poor sanitation. Illness is self-limited,
lasting 3-7 days, and serious sequelae are rare. The proportion of
patients with subconjunctival hemorrhage in the Mexico outbreak was
lower than previously observed; this might be explained by the
simultaneous presence in the community of other, unidentified
bacterial
or viral agents that cause conjunctivitis. Based on the
epidemiologic
observations and laboratory data, the outbreak in Mexico is
consistent
with AHC caused by CA24v.
In 1981, an epidemic of AHC occurred in south Florida after
enterovirus 70 was introduced from the Bahamas. In the Florida
epidemic, illness was spread throughout the community largely by
schoolchildren. Closing affected schools helped to control the
epidemic
(1,2).
References
Malison MD, Gunn RA, Hatch MH, Bernard KW, White MC. Acute
hemorrhagic conjunctivitis, Key West, Florida: an assessment of
risk
factors for introduction of illness into households and secondary
spread during the 1981 epidemic. Am J Epidemiol 1984;120:717-26.
2.Patriarca PA, Onorato IM, Sklar VEF, et al. Acute hemorrhagic
conjunctivitis: investigation of a large-scale community outbreak
in
Dade County, Florida. JAMA 1983;249:1283-9.
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