# MURINE TYPHUS--VECTOR BIOLOGY AND TRANSMISSION

> **NIH NIH R01** · UNIVERSITY OF MARYLAND BALTIMORE · 1993 · $198,359

## Abstract

Murine typhus is unique among the major arthropod-borne infections in that
it can be a household infection because of its intimate association with
commensal animals and their fleas.  Existing knowledge does not adequately
explain many important features and mechanisms which are involved in the
extraordinarily successful spread, establishment and maintenance of this
zoonosis.  This research proposal will examine, under controlled conditions
in the laboratory, using quantitative techniques, selected components and
interactions of the rickettsia-vector complex.

The project goals are:  (1) To study and define quantitatively the
rickettsia vector interrelationships in murine typhus infection, including
the course of infection and means of transmission, in three species of
fleas.  Factors such as rickettsial growth cycle, vector competence,
rickettsial virulence and cytopathology will be investigated; (2) To study
the reservoir mechanisms for Rickettsia typhi infection, in both fleas and
rats.  This work will also explore variations in the cellular and organ
locations of rickettsiae in both naturally and experimentally infected
fleas over a period of several generations.  To determine and study the
role of the rat as a reservoir of R.typhi, we will test the hypothesis that
reactivation of latent rickettsial infection occurs in a presumably immune
host long after the original infection, and that rickettsiae reappear in a
transmissible form that could infect a new series of vectors.  This will be
investigated in R.typhi-infected rats at different time points after
infection under various stress conditions (e.g. pregnancy and lactation,
other parasitic infections); and (3) To study the impact of physiological
and environmental changes on R.typhi, as it cycles between the arthropod
vector and mammalian host, may undergo changes in antigenic properties and
cellular fine structure.

## Key facts

- **NIH application ID:** 3127460
- **Project number:** 5R01AI017828-10
- **Recipient organization:** UNIVERSITY OF MARYLAND BALTIMORE
- **SAM.gov UEI:** Z9CRZKD42ZT1
- **Principal Investigator:** Abdu F Azad
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $198,359
- **Award type:** 5
- **Project period:** 1982-09-01 → 1994-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127460

## Citation

> US National Institutes of Health, RePORTER application 3127460, MURINE TYPHUS--VECTOR BIOLOGY AND TRANSMISSION (5R01AI017828-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127460. Licensed CC0.

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