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Biomedical subjects

M G Groves

Publications and source records attributed to M G Groves.

35 records · Page 2Linked to original sources
PubMed1981

Scrub Typhus antibody in cynomolgus monkeys (Macaca fascicularis) in Malaysia.

Using an indirect immunofluorescence technique, sera from 113 cynomolgus monkeys (Macaca fascicularis), trapped in Peninsular Malaysia, were screened for the presence of antibody to six prototype strains of Rickettsia tsutsugamushi combined into three polyvalent groupings: I--Karp, TA716, and TA763; II--Gilliam; and III--TA678 and TH1817. Fifteen percent (17/113) of the monkeys had antibody titers greater than or equal to 1:50 to one or more of the antigenic groups. Although a titer greater than or equal to 1:150 is generally considered indicative or prior Rickettsia tsutsugamushi infection, we selected a less than 1:25 titer as a conservative standard to insure non-infected animals. Using this criterion, 62 (55%) of the 113 monkeys were accepted for use in scrub typhus studies. The high prevalence of antibody to scrub typhus in the semi-arboreal cynomolgus monkey is in marked contrast to the low prevalence reported in the strictly arboreal silvered leaf monkeys (Presbytis cristatus). The results of this study indicate that cynomolgus monkeys should be rigorously screened for evidence of prior infection before they are included in experimental scrub typhus studies.

Animals↗
PubMed1980

Host defenses in experimental scrub typhus: mapping the gene that controls natural resistance in mice.

Natural resistance of mice to lethal ifections of Rickettsia tsutsugamushi, strain Gilliam, is controlled by a single, autosomal, dominant gene, which we have designated Ric, with r and s representing the resistant nd susceptible alleles, respectively. Using three sets of recombinant inbred mouse strains (BXD, BXH, and BXJ), the Ric locus was mapped to Chromosome 5 closely linked to the retinal degeneration (rd) locus. This linkage was confirmed by a backcross analysis. Based on the RI strains and the C57BL/6Ty-le congenic strain (the only proven Ric-rd cross-over), we estimate the recombination frequency between Ric and rd to be 0.015. Three presumptive Ric-rd recombinants detected among 93 backcross mice may represent caes of incomplete penetrance of the resistance allele rather than recombination. Analyis of th C57BL/6JTy-le congenic strain indicates that Ric is proximal to rd on Chromosome 5. If so, the correct gene order is Pgm-1-W-Ric-rd-Gus.

Animals↗
PubMed1978

Host defenses in experimental scrub typhus: genetics of natural resistance to infection.

Genetic resistance to lethal infection with Rickettsia tsutsugamushi was studied in over 30 inbred strains, inbred hybrids, and outbred stocks of mice. Inbred mice infected intraperitoneally with the Gilliam strain of R. tsutsugamushi showed three patterns of response: susceptible (A/HeJ, C3H/HeDub, C3H/HeJ, C3H/HeN, C3H/St, CBA/J, DBA/1J, DBA/2J, and SJL/J), resistant (AKR/J, BALB/cDub, BALB/cJ, C57BL/6J, C57L/J, and SWR/J), and selectively resistant (A/J). The selectively resistant pattern was characterized by random deaths occurring throughout the titration range and was also observed in three of the six outbred mouse stocks surveyed. No correlation was evident between the H-2 haplotype of inbred mice and their response to Gilliam infection. The progeny from five different Gilliam-resistant by Gilliam-susceptible inbred parental crosses were all resistant. Study of F(1), F(2), and parental backcross generations of BALB/cDub (resistant) and C3H/HeDub (susceptible) hybrids indicated resistance was dominant and was controlled by a single gene or a closely linked cluster of genes that were autosomal and not linked to coat color. The resistance of BALB/cDub mice was not due to an inability of host cells to support rickettsial growth, since C3H/HeDub and BALB/cDub embryo cell cultures supported similar growth of Gilliam organisms. C3H/HeDub mice, although susceptible to intraperitoneal Gilliam infection, were capable of mounting an immune response to Gilliam antigens, since subcutaneous infection was not lethal and did protect animals against subsequent intraperitoneal challenge with either the Gilliam or Karp strains of R. tsutsugamushi.

Animals↗
PubMed1975

Transmission of Ehrlichia canis to dogs by ticks (Rhipicephalus sanguineus).

Two strains of Rhipicephalus sanguineus acquired Ehrlichia canis by feeding as either larvae or nymphs on acutely infected dogs and, in subsequent instars, transmitted the agent to normal dogs. Three strains of R sanguineus transmitted E canis as adults after their larval and nymphal stages fed on infected dogs. More than 400 adult female ticks were fed on infected dogs as larvae or nymphs or both, but none transmitted E canis transovarially.

Alanine Transaminase↗
PubMedDate not supplied

Evaluation of a saliva test kit for feline leukemia virus antigen.

An enzyme-linked immunosorbent assay (ELISA) test kit for the detection of feline leukemia virus (FeLV) antigen in saliva was evaluated in 150 cats. Saliva and blood samples from all cats were tested for FeLV using the saliva ELISA kit and a plasma ELISA kit, respectively. These results were compared with indirect immunofluorescent antibody (IFA) testing of blood smears also obtained from each cat. The proportion of cats that tested positive were 10%, 7%, and 8% for each test, respectively. Using the IFA test as the gold standard, the saliva FeLV test had a sensitivity of 91.7% and specificity of 97.1%, while the plasma ELISA test had a sensitivity of 91.7% and specificity of 100%.

Animals↗
PubMedDate not supplied

The effect of mouse age on the determination of Rickettsia tsutsugamushi virulence.

The effect of age on the susceptibility of ICR mice to lethal intraperitoneal (ip), Rickettsia tsutsugamushi infections was tested with five virulent strains--Karp, Kato, Gilliam, TA763, and TH1817--and three strains of reduced virulence--TA678, TA686, and TA716. Susceptibility differences were noted only in the ICR mice inoculated with two of the strains of reduced virulence, TA716 and TA678. With both strains, mice in the 12-weeks and younger age groups had lower death rates than did mice in the 21-weeks and older age groups. Also, CBA/CaJ mice of varying ages were inoculated intravenously with large doses of the Gilliam strain to determine the effect of age on susceptibility to acute death syndrome (ADS). A progressive increase in ADS resistance was seen in the 4-, 8-, 12-, and 16-week-old age groups. This study indicates that the age of mice used to test the virulence of R. tsutsugamushi strains may be an important consideration, especially when testing the ip lethality of strains of reduced virulence.

Age Factors↗