Aerosol Q fever infection of the nude mouse

Athymic nude mice and euthymic littermate controls were exposed to 10(4) Coxiella burnetii organisms by small-particle aerosol. Antibody response with and without 2-mercaptoethanol treatment of serum was determined at various intervals after infection and serial kills were done to determine morphologic changes in both mouse phenotypes. Total antibody titers determined by the indirect fluorescent antibody technique to phase I and phase II C. burnetii were identical for both groups of mice. Microagglutinin titers determined on days 28 and 33 were abolished by 2-mercaptoethanol treatment of serum from both phenotypes, indicating that the antibody probably resided in the IgM fraction. Microscopically, the reaction to C. burnetii infection was similar in nude and euthymic mice on days 7 and 14. Later, the number and size of lesions attributable to Q fever diminished in euthymic mice. Infection was progressive in nude mice, with macrophage infiltration of most tissues, especially spleen and liver. Numerous rickettsiae were seen by immunofluorescence and electron microscopy in phagocytic vesicles of macrophages, many of which were dilated, giving the macrophage a vacuolated appearance. Results suggest that clearance of C. burnetii infection in mice is independent upon thymus-derived lymphocytes.

Cryptic epidemic of Q fever in a medical school

Pregnant sheep used in perinatel research were the source of a large outbreak of Q fever in 1980 among the faculty and staff of a medical school. Complement-fixation tests with phase II Coxiella burnetii antigen were positive in 81 persons, of whom 58 (71.6%) had Q fever during the first eight months of 1980. Microagglutination and/or indirect immunofluorescence tests of 485 sera were positive in an additional 56 persons. Only 41 of the 137 seropositive persons were involved in caring for or working with sheep; the remaining 96(70.1%) persons were located along the routes followed by sheep carts or had been exposed to sheep in other ways. Early in the outbreak few patients sought medical help. Later, most patients reported promptly and responded favorably to therapy with tetracycline. Sheep were removed from the campus in July 1980; cases ceased one month later. Other medical centers engaged in research with pregnant sheep should be alert to the risk of Q fever.

Evaluation of a killed phase I Coxiella burnetii vaccine in cynomolgus monkeys (Macaca fascicularis)

The protective efficacy of a killed, purified, phase I Coxiella burnetii vaccine was tested in cynomolgus monkeys. Monkeys vaccinated once with 30 micrograms of the antigen were challenged 6 or 12 months later with virulent phase I rickettsiae administered in small-particle aerosols. The vaccine provided only partial protection, since some of the challenged monkeys developed clinical signs of illness. However, the vaccinated animals did not develop pneumonia as determined by radiographic evaluation nor any hematologic or chemical changes except for an increase in fibrinogen. Although rickettsiae were isolated from peripheral blood in vaccinated monkeys, the rickettsemia persisted for only 1-2 days; whereas, organisms were recovered from unvaccinated animals for 6-7 days. All vaccinated animals had circulating microagglutinating antibodies to phase I and phase II antigens 6 and 12 months after vaccination.

[Serological studies in bovine Q fever]

A serologic study was carried out by means of the complement-fixation test (CFT) and the immunofluorescence titration method (ITM) of a total of 1250 blood samples from 13 farms, having records of abortions, retention of placentae, and endometritis. The comparison of CFT and ITM results showed that 44 (52.3 per cent) of the positive sera were altogether positive by the two methods, 24 (28.6 per cent) sera yielded positive reactions by CFT and negative ones by ITM, and 16 (19 per cent) sera proved positive by ITM and negative by CFT. In two cows that were experimentally infected with rickettsiae the complement-fixing antibodies appeared between the 8 h and 15th day, and persisted up to the 160th day, their titers reaching peak values of up to 1:160. Recorded was the dynamics of the complement-fixing antibodies in spontaneously infected cows that miscarried. In this case too the titers were not high--1:10 to 1:40. They persisted in the course of six months.

A study on the reservoir status of Q-fever in avifauna, wild mammals and poikilotherms in Uttar Pradesh (India)

Fifteen species of free-living birds (pigeon, mynah, house-sparrow, crow, vulture, owl, swallow, parrot, heron, duck, guinea fowl, hawk, kite, dove and peacock), 11 species of small/large wild mammals (rat, bandicoot, house mouse, shrew, bat, mongoose, ant eater, Jackal wild cat, chinkara and tiger) and 5 species of poikilotherms (snakes, python, tortoise, monitor and eel) were screened for evidence of Q-fever infection by the capillary agglutination test on sera to detect antibodies and/or by attempts to demonstrate Coxiella burnetii in samples of visceral organs. Sero-reactors were observed among mynah (19/69), owlet (1/6), pigeon (1/11), swallow (6/200), parrot (13/56), rat (3/21), shrew (1/24), bat (2/14) and snake (7/23). Eleven strains of the organism comprising 3 from mynah, 2 from rats, and 1 each from parrot, crow, swallow, bandicoot, chinkara and python were isolated. This appears to be the first record of natural Q-fever infection in free-living birds in India. C. burnetii was also recovered in 1 of 12 water samples processed from ponds. Possibility of contamination of ponds with C. burnetii from infected water-fauna has been discussed.

Sero-epidemiological studies on coxiellosis in animals and man in the state of Uttar Pradesh and Delhi (India)

The prevalence of antibodies to Coxiella burnetii, the causative agent of Q-fever, was studied in domestic animals either at the farm or at the slaughter house and man in Delhi and Uttar Pradesh (U.P.). Evidence of Q-fever infection was observed in 24.29% of 490 cattle, 16.79% of 536 sheep, 16.02% of 1011 buffaloes, 15.85% of 1937 goats, 14.67% of 184 pigs and 14.29% of 49 street dogs. Twenty percent of 55 dairy cows, 9.52% of 21 dairy goats and 5.71% of 35 dairy buffaloes were found positive for C. burnetii antibodies in their milk. Of 1636 human sera samples tested, 249 (15.22%) were positive. Human sero-positive reactors in U.P. and Delhi were 15.59% and 14.39% respectively. Factors of age, sex, season antibody titres, co-existance of Q-fever and brucellosis and public health significance of high Q-fever infection in meat and dairy animals under the prevalent socio-economic conditions are discussed.

[Combined use of serological tests for the purpose of the diagnosis and study of Q-rickettsiosis]

The combined use of the complement fixation test, the indirect immunofluorescent test and the ring precipitation test with C. burnetii antigen greatly enhances the effectiveness or serological study, as it allows not only to find out the spread of infection among population more completely, but also to differentiate, to a certain extent, "fresh" infectious process from immunological trace reaction. The arguments are presented in favor of introducing the antigen of C. burnetii, phase I, into practice, especially in surveying the sera of farm animals.

The occurence of coxiellosis among rodents and shrews in the Tarai area of Uttar Praedesh

Rodents and shrews were screened for serologic evidence of Coxiella burnetii. Attempts were made to isolate the organism from the spleen and liver. Seroreactors: total positive/total tested (% positive), in rats (Rattus rattus, R. norvegicus), ground shrews (Suncus murinus), bandicoots (Bandicota indica, B. bengalensis) and the house mouse (Mus musculus), respectively, were 13/105 (12.38), 6/42 (14.3), 2/15 (13.3) and 1/7 (14.3). Of the eight rickettsial isolants recovered including four from field and household rats, three from ground shrew and one from bandicoots, only three comprising one each from rat, shrew and bandicoot, could be typed as C. burnetii. This appears to be the first record of rodents and an insectivore as reservoirs of C. burnetii in India.

Experimental Coxiella burnetii infection of guinea pigs and mice

The susceptibility of five inbred strains of mice, designated DBA/1J, DBA/2J, C57BL/6J, Balf/CJ, and AKR/J, as well as outbred Hartley and Moen-Chase guinea pigs to infection with Coxiella burnetii by several routes was studied. The DBA/2J mice were more susceptible to infection and had higher mortality rates than other strains of mice. Guinea pigs were more susceptible to infection than mice. Lesions observed in the infected animals were similar to those previously described in man and experimentally infected animals.

[Cattle vaccination against Q fever in the rural district of Bratislava]

Cattle attendants on two farms in the Outer Bratislava district showed symptoms of Q-fever. The blood of the cows in these farms was found to contain antibodies to Coxiella burnetti and the causative agent of the disease was detected in milk samples of aborting cows by biological assays on hamsters (Mesocricetus auratus). The naturally invaded dairy cows with antibodies in the blood and heifers without antibodies were vaccinated with different doses of inactivated suspension of C. burnetii in stage I. A different antibody reaction to vaccination was obtained after the application of a four-fold amount of vaccine. It was proved that the animals did not excrete the causative agent of the infection even after administration of lower doses of the vaccine on the 120th day after vaccination.

[Infectious causes of perinatal mortalities in ruminants (author's transl)]

The advantages and disadvantages of the different diagnostic techniques e.g. pathological and microbiological studies, immunoglobulin and specific antibody determinations and fluorescent antibody studies in relation to these mortalities are discussed. The most important pathological lesions in the placentas and foetuses are described.

Experimental infection of Coxiella burnetii in chicken: clinical symptoms, serologic response, and transmission through egg

Young laying hens were infected with Coxiella burnetii to study egg transmission, clinical and serologic responses, excretion of the agent in feces, and its persistence in internal organs. No clinical symptoms were noticed. The birds developed good titers in a capillary agglutination test by 13 days postinfection (DPI), which peaked at 30 DPI and therafter declined gradually, becoming negative in some birds around 90 DPI. In vivo and in vitro egg transmission of the agent could not be demonstrated. C. burnetii was recovered at 90 DPI from spleen and liver but not from kidney and ovary.

[Regional epidemiologic characteristics of combined foci of tick-borne encephalitis, endemic rickettsioses and leptospirosis in Western Siberia]

The authors carried out complex study of combined foci of infections with natural foci in Western Siberia and their reflection in human pathology. The results of serological examination of 5917 persons and of 1743 of farm animals in respect to tick-borne encephalitis, Asian tick-borne rickettsiosis, Q-rickettsiosis, and leptospiroses are analysed. Affection of the population with all the four infections in all the landscape zones under study was shown; the intensity of this affection with different infections differed. Combined natural foci of the mentioned infections were found to be widespread; epidemiological significance of such combination was unequal in different ladscapes, this depending on the ladscape characteristics of the natural foci of infections under study and of different ways of transmission of their causative agents.