Related Experiment Videos
[Saint Louis encephalomyelitis in Hermosillo, Sonora, Mexico. Its epidemiology]
Abstract:
In a warm desertic and irrigated region, with population 250 000 Northwest of Mexico, in Hermosillo, Sonora, along 8 weeks, 51 patients showed the following clinical data: fever, vomiting, neck rigidity, drowsiness and increase of cells and proteins in the CSF. In 12 patients good correlations were found between positive serologic results using SLE antigen by means of HI, CF and NT. Four paired sera showed fourfold increases in titers to SLE by means of HI or CF. With VEE antigen no such increases were found. The cases were scattered geographically, most of them occurred within an urban area, and affected people in 13 localities. The outbreak developed from August to September, 1974, the attack rate was 22/100 000, 69% of the patients being children under 15 years of age. The case fatality rate was 20%. A prosperous chicken industry existed in the region and epizootics were not reported in either domestic or wild animals at that time.
Insights
An outbreak of meningitis in Hermosillo, Mexico, affected 51 patients, primarily children, with a 20% fatality rate. Serologic tests suggested a link to SLE virus (SLE), distinct from VEE virus.
Area of Science:
- Epidemiology
- Virology
- Neurology
Context:
- An 8-week outbreak occurred in Hermosillo, Sonora, Mexico, a warm desertic and irrigated region with a population of 250,000.
- The outbreak primarily affected children under 15 years of age, with an attack rate of 22/100,000.
- Clinical manifestations included fever, vomiting, neck rigidity, and drowsiness, with elevated cells and proteins in cerebrospinal fluid (CSF).
Purpose:
- To investigate an outbreak of meningitis in Hermosillo, Sonora.
- To identify the causative agent and serologic correlations.
- To determine the epidemiological characteristics and fatality rate of the outbreak.
Summary:
- Fifty-one patients presented with meningitis symptoms. Twelve patients showed positive serologic results for SLE virus (SLE) using hemagglutination inhibition (HI), complement fixation (CF), and neutralization tests (NT).
- Four paired sera demonstrated a fourfold increase in SLE antibody titers via HI or CF, while no such increase was observed with Venezuelan Equine Encephalitis (VEE) virus antigen.
- The outbreak spanned August to September 1974, with a case fatality rate of 20%. No animal epizootics were reported.
Impact:
- Identified SLE virus as a potential cause of the meningitis outbreak.
- Highlighted the vulnerability of children to this specific viral agent.
- Provided crucial epidemiological data for public health response and future prevention strategies.