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V. Varga (State Health Institute, Nitra, Slovakia)

S u m m a r y :
An explosive epidemic of Q-fever that occurred at Jedľové Kostoľany (Nitra District) in April 1993, had an unusual mode of transmission, unprecedented in Slovakia. The submitted casuistics can be very instrumental for both health workers and lay public. The bulk of infection was spread in the local pub through contaminated garments of animal attendants assisting the abortions and births of goats in a large capacity breed of Gemersan Co. By their repeated visits to the local pub the infection was most probably spread to other guests by aerosol. Affected with Q-fever were totally 113 persons (103 males, 10 females). Out of them 95 were infected through the contact with the goat attendants (84 per cent), and 18 were occupational diseases after direct contact with the infected goats. The human epidemic of Q-fever facilitated to trace an ongoing epizootic of coxiellosis among the herd of goats of Gemersan breed. In order to stop further spread of infection among humans and to contain the outbreak of coxiellosis among animals extensive epidemic and epizootic measures have been taken.
Key words: Q-fever, Coxiella burneti, coxiellosis, explosive epidemic of Q-fever
I n t r o d u c t i o n :
Q-fever was first described by Derrick in 1937 in an outbreak of a febrile disease in workers of a meat factory in Brisbane, Australia, and its causative agent identified as Coxiella burneti. Some years later it was described in America. During the World War II it occured in Balkan and in Italy. Currently it occurs worldwide (3,8). In Slovakia Q-fever was first diagnosed in 1954 after importation of infected sheep from Roumania (2). First human diseases were found among agricultural workers in West Slovakia. In the following years, epizootic outbreaks of coxiellosis spread by infected animals, cotton and wool imported from abroad as well as the outbreaks of Q-fever in humans were reported virtually from all parts of Slovakia (6,7). The overwhelming part of them (98 per cent) were of accupational nature (5,6,10). Since 1990 no case of Q-fever in humans was reported (1,4) until 1993. In 1993 the zero incidence was after 3 years interrupted by an epidemic at Jedľové Kostoľany.
Charakteristics of the epidemic :
First cases were signalled by a GP on 14 April, 1993, who over 2 days saw and treated 25 persons from Jedľové Kostoľany running high fever. He at the same time warned that the same number of cases with similar symptomatology in persons from the same village were treated by emergency medical service doctor during Easter Holidays. In their clinical picture high fever, chills, headaches, arthralgia and anorexia prevailed. Epidemiological investigation was focused on establishing the diagnosis, disclosing the source of infection and identifying the mode of transmission. The necessary history data were taken as well as biological samples for examination, and an active search for further cases was accomplished. Hospotalization of severe cases and their adequate treatment wereensured.
Results of epidemiological investigation :
From the obtained epidemiological data followed that only adult males of different professions fell ill. A single history item common to all the interviewed patients was the visit of the local pub. Among clinical data in 17 hospitalized high erythrocyte sedimentation rate was proved, and in 6 of them the elevated levels of aminotransferase activity were revealed. Biological material was taken for culture, isolation of virus and serologic tests to legionellosis, Mycoplasma pneumoniae, brucellosis, listeriosis and Q-fever. On the basis of clinical picture further epidemiological investigation was directed to zoonoses in humans and extended to the search of infections in domestic animals. 168 heads of home raised livestock were investigated (cattle, sheep, goats), and 400 heads of livestock at the local cooperative were tested - all with negative results. Within the objects of the local cooperative also the large-capacity breed of goats of Gemersan Co. were placed, and 6 animals attendants were accomodated in the compounds. Workers of the Gemersan Co. refused to provide any information about the health of the animals. However, inspection of the compounds revealed several carcasses of kids. Further data were then obtained through the veterinary service. Goats (1181 in number) were purchased in September 1992 from Bulgaria and temporary placed in Rimavská Sobota District. During the quarantine a few of the tested goats were positive of coxiellosis and slaughtered. In January 1993, 500 of the goats were transferred to the componnds of the Agricultural Cooperative at Jedľové Kostoľany. At the end of February 1993 several abortions of the goats occurred and several of them died. In March of the same year massive losses of the newborn kids occurred. The breed at that time was lacking any veterinary care. An outbreak of coxiellosis was later confirmed by serologic tests yielding 38 per cent positivity for coxiellosis. The serosurvey was carried out on our request by the State Veterinary Service.
After disclosing the source of infection - the affected goats of Gemersan Co., the next important discovery in the chain of the spread of infection was identification of the modes of transmission. From 4 animal attendants the information was obtained on their often visits to the local pub without changing their working garments. The occurrence of the disease in the visitors of the pub arose our suspicion that the infection could be introduced to the pub through the contaminated working clothes of animal attendants, and that the infection was most probably spread through the aerosol of the contaminated dust.
Graph 1 illustrates the time sequence of the cases within the outbreak. The first 4 unrecoglized cases were misdiagnosed as influenza in March 1993 in animal attendants at the Gemersan goat farm. The outbreak acquired an explosive character in April with a peak on the 14th of April, 1993 (17 cases), and the last case occurred on the 18th of May, 1993.

graf 1

The highest age-specific incidence was in the age group 25-34 y. (Graph 2). From the total population of Jedľové Kostoľany - 1,142 permanent inhabitants - 101 fell ill (8,8 per cent). 12 diseases were in persons who during the incriminated time visited the village and came into contact with the goat attendants. Thus the total number of affected in the epidemic accounted for 113 (103 males, 10 females). Out of that number 95 fell ill after the contact with animal attendants, 18 were infected directly from the affected animals (5 goat attendants, 10 workers of the cooperative,

graf 2

1 veterinary doctor, 1 worker of hygienic service and 1 animal dealer of Branko Co). All those were classified as occupational disease.
Hospitalized were 42 patients (37,2 per cent). Out of 83 clinically examined patients 55 suffered pneumonia (48,7 per cent), in 46 elevated hepatal tests were found (46,7 per cent). In 33 these tests were not performed for various reasons.
Serological tests (complement-binding) were carried out in all 113 patients. As positive were considered the titres 1:16 and higher. All 113 sera were found positive. Repeated tests were carried out in 73 cases and significant increase of titres was found in 37,2 per cent of the samples. Positive findings were confirmed by more sensitive methods (microagglutination, ELISA IgM, IgG); out of 96 samples 72 were positive.
In addition to 113 patients serological examinations for Q-fever were performed in further 60 persons: 6 goat attendants and 12 workers of the cooperative who were in contact with the affected animals (of them 3 were serologically positive), 16 workers of Branko Co. who slaughtered 40 kids from the incriminated herd for Easter market (all serologically negative) as well as all the persons from Jedľové Kostoľany and the adjacent villages in who fever was found during the epidemic, even when their clinical picture did not correspond to Q-fever (all those sera were negative).
E P I D E M I C M E A S U R E S :
All citizens of the village were under thorough medical surveillance; temporary all congregations of the people were prohibited; the animal attendants were restricted to leave their work place without thorough sanitary measures; consumption of goat milk and its processing was prohibited. The State Veterinary Service issued strict sanitaryregulations to eliminate coxiellosis from the goat breed, including vaccination of all the livestock in the village against coxiellosis.
D I S C U S S I O N :
Q-fever infection in our conditions is most commonly spread through the contact with biological material from the infected animals. Therefore, the diseases are mostly of occupational nature, and outbreaks in humans occur in immediate association with animal breeds in which the infection is mostly in an inapparent form and activates only during the pregnancies of the animals. During abortions and births Coxiella burneti is usually shed into external environment in amniotic fluid (3).
However, the epidemic at Jedľové Kostoľany was caused by 4 animal attendants who by their repeated visits to the local pub in unchanged working garments contaminated the environment and thus infected 95 persons. Coxiella has been proved on pieces of garments in question also in Romney Marsh, England. Passive transmission of Coxiella burneti by clothes, shoes, hands and hair has been confirmed also by other authors (9). From the above mentioned follows that the Q-fever infection can be spread to people by contaminated garments, mostly in indoor settings as was evidenced by described epidemic in which 84 per cent of the affected were infected through this specific mode of transmission.
C O N C L U S I O N S :
The explosive epidemic of Q-fever at Jedľové Kostoľany in April, 1993, that interrupted the 3-yers˘ zero incidence of this disease in Slovakia was exceptional in following points:
1. The mode of transmission unprecendent in Slovakia; only 16 per cent of cases were occupational nature.
2. 51,3 per cent of cases were found in an active search.
3. The highest incidence was in 25-34 year-olds - distinctly from literary data placing the peak incidence to the 45-year-olds and older (5,6,7) which was corresponding to the age of visitors of the epicentre of the epidemic - the local pub.
4. Coxiellosis in goats was identified only on the basis an epidemic of Q-fever in humans, and veterinary measures were introduced only on request of hygienic service.
5. A retrospective analysis in Rimavská Sobota District revealed that 11 workers of Gemersan Co. suffered a febrile disease in the past which was later serologically confirmed as Q-fever of occupational nature.
[1] Audičová, M.: Analysis of Epidemiological Situation in Slovak Republic, 1991-1992 (in Slovak), unpublished communication.
[2] Bárdoš,V., Šimková,A.: Q-fever in Slovakia (in Slovak), Bratisl. Lek. Listy, 36, 1956, 17, p. 18-20.
[3] Kméty,E.: Special Epidemiology (in Slovak). 1. Martin, Osveta 1985, p.132-133.
[4] Masár,I.: Epidemiological Situation in Slovakia, 1985-1990 (in Slovak), Správy SEVAC, No 3
[5] Palanová,A.: A Contribution to the Epidemiology of Q-fever in Central Slovakia (in Slovakia). Banská Bystrica, PhD thesis 1972, p.1-184.
[6] Palanová,A., Řeháček,J., Brezina,R.: Rickettsiae and Rickettsiases Diseases. 1. Bratislava , Veda 1978, p. 435-441.
[7] Pospíšil,R., Baloghová,D.: Occurence of Q-fever in east Slovakia. Košice, 1993, unpublished paper.
[8] Raška,K.: Epidemiology (in Slovak). 3. Martin, Osveta 1959, p. 412-417.
[9] Řeháček,J., Tarasevich,I.V.: Acari-borne Rickettsiae and Rickettsioses in Eurasia. 1. Bratislava, Veda 1988, p. 292-300.
[10] Surveillance of Zoonoses (Annual Reports 1976-1985). Committee for Zoonoses (in Slovak). Bratislava, Institute of Veterinary Information.