# TRANSMISSION AND CONTROL OF CALIFORNIA-GROUP VIRUSES

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 1988 · $94,634

## Abstract

La Crosse (LAC) encephalitis virus is an important mosquito-borne agent
occurring throughout the eastern half of the United States.  Feral
populations of the vector, Aedes triseriatus, breed primarily in small
water-containing tree holes, but the mosquito has adapted to discarded auto
tires and other small man-made water containers.  The continuing long-term
objective of this project is to determine and quantify the factors that
influence the epidemiology of the disease.

The current working hypothesis is that vertebrate amplification is not
essential for LAC virus survival in localities where the Aedes triseriatus
population has a high maternal vertical transmission rate (MVTR), i.e., 60%
or higher.  Venereal transmission is the probable compensating mechanism
for virus erosion during vertical transmission.  Virus survival becomes
increasingly dependent on vertebrate amplification as the MVTR decreases.

Two current major objectives include determining venereal transmission
rates under various mating/bloodfeeing schedules, and follow-up on
preliminary results indicating that Ae. triseriatus that feed on deer blood
containing Jamestown Canyon (JC) virus N antibodies lose their ability to
transmit LAC virus.  Deer are a major blood meal source of Aedes
triseriatus and such an interference phenomenon could be a major factor
explaining the discontinuous "pocket" distribution of clinical La Crosse
encephalitis.

Another major objective is to determine LAC virus transmission thresholds
and to devise control strategies that will reduce feral Ae. triseriatus
populations to levels sufficiently low that transmission to amplifiers is
interrupted.  Insecticide treatment of natural oviposition sites
supplemented if necessary be treated ovitraps is the first approach to be
employed.  All of these investigations will require only more or less
standard entomological and virological methods.

Other main objectives are the development of an improved double antibody
sandwich enzyme-linked immunoassay for rapid LACV isolation from individual
mosquitoes, and adapting the cuticular growth bands method for determining
the calendar age of individual Ae. triseriatus,  The former will greatly
facilitate virus assay in may kinds of experiments and the latter will
provide invaluable insights on Ae. triseriatus field behavior during the
critical first 12-14 days of adult life.  The cuticular aging method, if
successful, should provide a new level of confidence in vector population
models.

## Key facts

- **NIH application ID:** 3124368
- **Project number:** 5R01AI007453-22
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **SAM.gov UEI:** LCLSJAGTNZQ7
- **Principal Investigator:** GENE R. DE FOLIART
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $94,634
- **Award type:** 5
- **Project period:** 1977-12-01 → 1990-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3124368

## Citation

> US National Institutes of Health, RePORTER application 3124368, TRANSMISSION AND CONTROL OF CALIFORNIA-GROUP VIRUSES (5R01AI007453-22). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3124368. Licensed CC0.

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