Original scientific paper
Q - fever epidemic at Ogulin in 1952 and its occupational featur
B. Cvjetanović
; Škola narodnog zdravlja Medicinskog fakulteta Zagreb
J. Fališevac
; Bolnica za zarazne bolesti Zagreb
F. Mihaljević
; Opća bolnica Ogulin
D. Kozmar
; Zavod za mikrobiologiju Veterinarskog fakulteta Zagreb
E. Topolnik
; Zavod za mikrobiologiju Medicinskog fakulteta Zagreb
J. Vesenjak-Zmijanac
Abstract
Q-fever in Yugoslavia was first diagnosed and identified by Mihaljević in Zagreb (1) in 1948. Many sporadic clinical cases have been diagnosed since at Doboj (33), Gračanica (33). Banja Luka (33), Skoplje (34), Novi Pazar (35). Zagreb (2, 36), Beograd (37), Sarajevo (38), Travnik (39) and possibly Split (33). ln addition to sporadic cases five epidemics broke out so far with 5-35 cases each: at Pančevo (3) in 1949, at Kopar (40), Sokol (6, 41) and Gračanica (33) in 1950 and al Ogulin in 1952. It should be pointed out that serological analyses of iuhabitants of all republics, except Slovenia, imply a much wider contact with C. burneti (33) than shown by identified cases and epidemics. An outbreak of Q-fever in the town of Ogulin, which occurred in April 1952, is reported. That is the first epidemic of this disease known in Croatia. The authors describe shortly the progress of the knowledge about Q-fever and especially about the prevalence of the disease both in the world and Yugoslavia. The occupational character of the Q-fever epidemic at Ogulin is put forward. The first case was a butcher working at the town slaughterhouse. Later on also another butcher developed the disease. Other slaughterhouse workers showed positive C. F. tilers - 1 : 10 to 1 : 80. This is a proof of the high exposition of this profession to the infective agent. Moreover, a woman from the laboratory staff working on C. F. tests anti inoculating guinea-pigs for isolation of C. burneti from milk collected at Ogulin developed the disease as well. This implies that Q-·fever should be added to the list of occupational diseases, and that proper steps should he undertaken lo protect the workers exposed to this infection.
Clinical features
26 serologically proved cases are listed in Table 1 and clinically analysed. According to clinical and epidemiological data there were some other cases as well but for various reasons the disease could not be proved serologically. In all 26 cases symptoms characteristic of U-fever, i. e. headache, especially in the frontal region, malaise, chilliness, high fever. pains in various parts of the body, sweating etc. were present. There were no definite symptoms of upper respiratory tract infection. In eight cases pneumonia was found by X-ray diascopy and only in some of them also by clinical examination. Pulmonary involvement was unilateral in six cases, and bilateral in two. All of them had all characteristics of primary atypical pneumonia. Because the patients with pneumonia had been in more intimate contact with animals it has been suggested that pneumonia might have resulted from more massive infection (dust). As to the gastrointestinal tract there was nothing significant, except diarrhoea in two cases and vomiting in one. Diarrhoea is rare in Q-fever and perhaps it occurs only in infection by ingestion. The spleen was enlarged in two cases only. B. S. R. was moderately increased both in cases with and those without pneumonia. The febrile period was between 4-14 days. The mean being 8 days both in cases without pneumonia and in those where the lungs were involved. There were no complications or fatal cases. Some patients late in convalescence complained of weakness, headache and sweating. Penicillin or sulfonamides treatment did not influence the course of the illness. Aureomycin and chloramphenicol were applied late so that it was not possible to assess their effectiveness. Serological findings were not especially discussed here and they were presented only lo prove the clinical diagnosis on men (see table 1). C. F. tests were carried out also on animals and men lo help epidemiological investigations.
Eiridemiology
An epidemic or Q-fever in the town or Ogulin with about 2000 inhabitants, broke out in the beginning of April. 1952. The Q-fever outbreak started on the peak of a respiratory disease clinically diagnosed as influenza and pneumonia, but no laboratory tests were made (sec Fig. 3.). There were 26 serologically proved cases mostly young males who had had a contact with domestic animals. Clinical and epidemiological observations gave evidence of more cases of Q-fever in this epidemic. The sudden outbreak of the epidemic and its short duration suggested a short exposition to the infection (see Graph 4). Later on it was realised that some sporadic cases of Q-fever occurred in May, July and November, and many healthy people (about 20%) showed a residual C. F. titer. This was proof of a permanent and widely spread infection in the area. In order to find out the source of infection we started testing cows with C. F. particularly those having some epidemiological connection with Q-fever cases. However, not one of them was found positive. The isolation of C. burneti by inoculation of guinea-pigs with milk taken from the town dairy center (collecting milk from this * The antigens were placed at the disposal of the Microbiological Department of the Medical Faculty-which carried out all serological est - by the World Health Organization. Division for Zoonoses (M. Kaplan, V. M. D.). area) yielded no positive results either. Then we proceeded to investigate sheep and found that those from the herds slaughtered at the town abattoir just prior to the epidemic had been positive. The butcher buying these sheep in the village and laughtering them in the town was first to develop the disease. However the way the infection spread was not clear at all. So we were forced to follow up all possible factors which might have played a role in spreading the infection. Water was the only common factor in all cases, but it was pure and clorinated. Milk was not considered as a cause of infection because only 50% of patients were drinking milk and all the cows were negative. No useful epidemiological data of major significance could be obtained from the examination of the patients' living and working quarters. No history of a tick bite was heard from any patient: and no man to man transmission was observed. Four of the infected people were visiting the abattoir and handled in one way or another the meet of the sheep killed. A few were buying and eating the meet of those animals but many more had no contact with the animals or their products. The abattoir, its stable and refuse dump was close to each other and all were in the vicinity of the town square (used also as a market) of the hotel and of the Community Home (sec Fig. 5). All those that developed the disease used to pass often near by either for the purpose of marketing or going to the hotel or to meetings at the Community Home. As shown in Graph 4 about ten days before the first case developed the disease, and before the sheep from the infected herd were slaughtered, the temperature was well above zero Co. There was a north wind of considerable strength but there was no rainfall. Such conditions were bound lo promotre the formation of dust which the wind could easily carry to the objects concerned. The dust so created at the slaughterhouse. its stable and refuse dump may have contained at that time a considerable amount of the infective agent. It is obvious that passers-by could thus easily be infected. Six of our cases were attending the meeting in the Community Home and all developed the disease 20 to 22 days later. Only one was present at the meeting on the town square and he became ill after 20 days. Taking into consideration that the infective agent was widely spread al that period of the year when sheep have their young and are slaughtered, the infection could spread at the same time from many foci by different ways. Some clinical observation on the prevalence or pulmonary and intestinal involvement support it. It is very likely that the reservoir of Q-fever in the area of Ogulin are the tick invading the sheep particularly in spring. Of those ticks there are two (Hyaloma dromedarii and Rhipicephalus sanguincus) which have been proved to be the reservoir of Q-fever in nature. lt is worth noting that the epidemic broke out on the peak of the Lick invasion (see Fig. 6). The outbreak of Q-fever in men appeared at a time when sheep were highly invaded by licks transmitting the disease. Moreover, the sheep themselves were at that lime most infective precisely because they were breeding. This happened in the earl)' spring when the disease, originally an epizootic was so prevalent among animals that it was easily transmitted to humans. The sporadic cases in men during the year prove permanent presence of the infection among animals. Those are the factors causing the endemo-epidemic pattern of Q-fever in the area of Ogulin, diagnosed recently hut obviously present for years.
Keywords
Hrčak ID:
187237
URI
Publication date:
6.3.1953.
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