Related Experiment Videos
An outbreak of plague in Hlegu, Burma in 1977
Abstract:
An outbreak of plague occurred in Hlegu Town, Burma in February and March 1977. Altogether 14 bubonic plague cases, with 2 deaths were reported, mostly children under 15 years of age. Twice as many males as females were affected. A retrospective investigation showed that a rat fall took place in the last week of January. Only 9.5% of the rodents which died in the epizootic were found to be infected with Y. pestis; this apparent low infection rate probably resulted from the inclusion in the survey of some dead rats which died of other causes. 14.5% out of 48 trapped rodents were found to be serologically positive. The general flea and cheopis indices were rather high, perhaps because fleas were found to be partially resistant to DDT and also because spraying of insecticide did not effect fleas on the hosts. The cheopis index in Hlegu Town was 1.17, and less than 0.5 in Hlegu suburb (Yankin-Yat) where no epizootic was reported. An active case search revealed 76 suspected plague cases out of which 11 were found to have bubonic plague. A field trial showed that plague vaccination during the outbreak did not result in a rise of detectable antibodies in persons inoculated.
Insights
A 1977 plague outbreak in Hlegu Town, Burma, affected mostly young males. Investigations revealed a rat fall, high flea indices, and limited vaccine effectiveness during the event.
Area of Science:
- Epidemiology
- Infectious Diseases
- Zoonotic Diseases
Background:
- An outbreak of bubonic plague occurred in Hlegu Town, Burma, in February-March 1977.
- The outbreak primarily affected children under 15, with males disproportionately impacted.
- A preceding rat fall event was identified as a potential trigger.
Purpose of the Study:
- To investigate the epidemiology of the plague outbreak in Hlegu Town.
- To identify risk factors and contributing elements to the outbreak.
- To evaluate the effectiveness of plague vaccination during the event.
Main Methods:
- Retrospective investigation including rodent and flea surveys.
- Serological testing of trapped rodents.
- Active case finding and clinical assessment of suspected cases.
- Field trial to assess plague vaccination efficacy.
Main Results:
- 14 cases of bubonic plague with 2 deaths were reported.
- Low infection rate (9.5%) of Yersinia pestis in deceased rodents, potentially due to non-plague deaths.
- High flea indices, possibly linked to partial DDT resistance and ineffective insecticide spraying.
- Plague vaccination during the outbreak did not induce a detectable antibody response.
Conclusions:
- The outbreak was associated with a rat fall and high flea indices, complicated by insecticide resistance.
- Limited effectiveness of plague vaccination was observed during the active outbreak phase.
- Further research on vector control and vaccination strategies in outbreak settings is warranted.