Epidemic transmission of enterically transmitted non-A, non-B hepatitis in Mexico, 1986-1987
O. Velazquez, H. C. Stetler, C. Avila, G. Ornelas, C. Alvarez, S. C. Hadler, D. W. Bradley and J. Sepulveda
Residency Program in Applied Epidemiology, Secretariat of Health, Mexico City, Mexico.
Outbreaks of acute hepatitis occurred in Huitzililla and Telixtac, two
rural villages 70 miles south of Mexico City, Mexico, in late 1986. The
first outbreak began in Huitzililla in June of that year, 1 month after the
start of the rainy season. A census revealed 94 icteric case subjects, for
an attack rate of 5%; two women died. Attack rates were higher for persons
older than 15 years (10%) than for younger persons. A case-control study
showed that illness was highly associated with water-related factors. The
second outbreak began in August 1986 in Telixtac. There were 129 case
subjects, for an attack rate of 6%; one woman died. Epidemiologic findings
were similar to those in Huitzililla, except that most disease transmission
was not linked to unsafe water sources. None of 62 case subjects in
Huitzililla and only 2 of 53 case subjects in Telixtac tested had
serological evidence for recent infection with hepatitis A or B. Two of
eight stool samples from Huitzililla and one of the eight stool samples
from Telixtac were positive by immune electron microscopy for 32- to 34-nm
viruslike particles similar to those seen in cases of enterically
transmitted non-A, non-B hepatitis from Asia. To our knowledge, these
investigations document for the first time the epidemic transmission of
enterically transmitted non-A, non-B hepatitis virus in the Americas.
