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Comparison of three methods used to isolate dengue virus type 2
Abstract:
During the 1969 dengue epidemic in Puerto Rico, human sera and Aedes aegypti mosquitoes were collected for virus isolation and identification. Three methods of isolation were used and compared. In the first method, we inoculated newborn mice by the intracranial route, noted any signs of illness, and serially passed specimens in mice until virus was isolated. In the second method, we inoculated tube cultures of LLC-MK(2) cells, noted any cytopathic effect (CPE), and assayed fluids for virus by plaque formation in LLC-MK(2) cell monolayers. The third method was different from the second only in that the original specimens were first inoculated into fluid cultures of Singh's A. albopictus cells. No significant CPE was seen in LLC-MK(2) cultures; however, distinct syncytial CPE was observed in A. albopictus cells. About the same number of virus isolates were made in each isolation system. Virus isolates from both sera and mosquitoes were identified as dengue type 2 by a plaque-reduction neutralization test in LLC-MK(2) cells. The utility of the three methods, individually or in combination, is discussed and related to diagnostic and epidemic situations.
Insights
During a 1969 dengue epidemic, researchers compared three virus isolation methods. Dengue type 2 virus was successfully isolated from human sera and mosquitoes using all methods, with A. albopictus cells showing distinct cytopathic effects.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- Dengue virus outbreaks pose significant public health challenges.
- Effective virus isolation and identification are crucial for disease surveillance and control.
Purpose of the Study:
- To compare the efficacy of three different virus isolation methods during a dengue epidemic.
- To identify the dengue virus serotype responsible for the 1969 Puerto Rico epidemic.
Main Methods:
- Human sera and Aedes aegypti mosquitoes were collected during the 1969 dengue epidemic.
- Virus isolation was attempted using newborn mice, LLC-MK(2) cell cultures, and A. albopictus cell cultures.
- Virus identification was performed using plaque-reduction neutralization tests.
Main Results:
- All three isolation methods yielded comparable numbers of virus isolates.
- Distinct syncytial cytopathic effect (CPE) was observed in A. albopictus cell cultures, unlike LLC-MK(2) cultures.
- Isolates from both human sera and mosquitoes were identified as dengue type 2 virus.
Conclusions:
- The study demonstrated the utility of multiple virus isolation techniques for dengue surveillance.
- Aedes albopictus cell cultures showed promise for detecting dengue virus due to observable CPE.
- Effective virus isolation and identification are vital for managing dengue epidemics.