Q fever in Northern Ireland

A history of bovine tuberculosis eradication policy in Northern Ireland

Despite many years of state-sponsored efforts to eradicate the disease from cattle through testing and slaughter, bovine tuberculosis (bTB) is still regarded as the most important and complex of animal health challenges facing the British livestock agricultural industry. This paper provides a historical analysis of the ongoing bTB statutory eradication programme in one part of the UK – Northern Ireland (NI) – which began in 1949 as a voluntary scheme, but between 1959 and 1960 became compulsory for all cattle herd-owners. Tracing bTB back through time sets the eradication efforts of the present day within a deeper context, and provides signposts for what developed in subsequent decades. The findings are based primarily on empirical research using historical published reports of the Ministry of Agriculture and state documents held in the public archives in NI, and they emphasize the need to consider the economic, social and political contexts of disease eradication efforts and their influences on both the past and the present.

A large Q fever outbreak in the West Midlands: clinical aspects

In the spring of 1989 the largest outbreak of acute Q fever recorded in the United Kingdom occurred in Solihull and surrounding areas of the West Midlands. The diagnosis was confirmed in 147 people, mainly males of working age. Windborne spread from farmland to the south of the urban area was the most likely route of infection. Fever was the commonest symptom, seen in 101/102 (99%) cases, followed by weight loss reported by 83/101 (82%). Headache, often severe, was experienced by 69/101 (68%). The commonest respiratory symptom was breathlessness, 65/102 (64%), followed by cough, 52/102 (51%), and chest pain, 46/102 (45%). Neurological features, seen in 23% of cases, were more prominent in this outbreak than is commonly recognized. Persisting ill health 6 months following the acute episode not due to chronic Q fever was also a prominent feature of this largely urban outbreak.

Zoonotic infections in Northern Ireland farmers

Evidence of past zoonotic infection was investigated serologically in randomly selected Northern Ireland farmers. The percentage of farmers with antibody was: Brucella abortus (0.7), Leptospira interrogans serovars (8.1), Borrelia burgdorferi (14.3), Toxoplasma gondii (73.5), Coxiella burnetii (28.0), Chlamydia psittaci (11.1) and Hantavirus (1.2). The results show that Northern Ireland farmers have been exposed in the past to zoonotic infections. It is not known if these infections contributed to ill health in farmers but it is now time for the health of farm workers and their medical services to be reassessed.

Clinical Q fever in Northern Ireland 1962-1989

Q fever was diagnosed in 443 patients in Northern Ireland between 1962 and 1989. From 1986 onwards there was an increase, which peaked in 1989 with 107 cases of whom 47 were infected in Ballycastle, Co Antrim. There were three outbreaks and 21 clusters of patients with Q fever. Most cases were in April and May which correlated with the peak lambing and calving season. Q fever mainly affected males in the 40-49 year old age group. County Antrim had the highest prevalence rate of 40/100,000 population and also had the most sheep. The number of sheep in Northern Ireland has doubled in the past ten years. Q fever was strongly associated with occupation and animal contact. Eighty-seven patients (19.6%) drank unpasteurized milk. The commonest presenting illnesses were pneumonia (62.8%), influenza-like illness (24.6%), involvement of the heart (9.0%) and hepatitis (1.6%). Thirty-two patients (7.2%) had endocarditis, 20 of whom had prosthetic valves and three of whom died. Coxiella burnetii was present on valves removed from seven patients.

Q fever - a review

Q or "query" fever is a zoonosis caused by the organism Coxiella burnetii. Cattle, sheep and goats are the most common reservoirs of this organism. The placenta of infected animals contains high numbers (up to 10(9)/g) of C. burnetii. Aerosols occur at the time of parturition and man becomes infected following inhalation of the microorganism. The spectrum of illness in man is wide and consists of acute and chronic forms. Acute Q fever is most often a self-limited flu-like illness but may include pneumonia, hepatitis, or meningoencephalitis. Chronic Q fever almost always means endocarditis and rarely osteomyelitis. Chronic Q fever is not known to occur in animals other than man. An increased abortion and stillbirth rate are seen in infected domestic ungulates.Four provinces (Nova Scotia, New Brunswick, Ontario and Alberta) reported cases of Q fever in 1989.A vaccine for Q fever has recently been licensed in Australia.

Q fever in the United Kingdom and Ireland

In Britain, Q fever in man was first reported in 1949. Two years later a serological survey of cattle revealed a prevalence of infection of 2.1%. In the 1970's prevalences of 4.5% and 3.1% were encountered respectively in cows that had aborted or calved normally in central England. In sheep, antibodies to C. burnetii have been detected in approximately 2.8% of sera examined for diagnostic purposes and 0.6% of sheep awaiting export. Since 1975 fewer than 10 incidents of C. burnetii associated disease in cattle have been reported annually while the figure for sheep has been even smaller. Between 100 and 200 cases of human Q fever are encountered annually. The majority are sporadic but occasionally large outbreaks occur. Direct contact with farm livestock or other animals cannot always be established. Despite Public Health interest in Q fever the low economic significance of C. burnetii infection of farm livestock limits opportunities for conjoint medical-veterinary epidemiological investigations. In Ireland, the patterns of animal infection with C. burnetii and of human Q fever are broadly similar to those in Britain.

Q fever endocarditis

Despite a worldwide distribution of Coxiella burnetii, only single cases of Q fever endocarditis have been reported outside Great Britain and Australia. We present 10 patients; five were female, only four had a history of environmental exposure, and the mitral valve was involved as commonly as the aortic stenosis, and three patients had a prosthetic valve. We confirm the importance of hepatic involvement, thrombocytopenia and hypergammaglobulinemia as diagnostic features. Diagnosis was established by finding and elevated complement-fixing antibody to Phase I C. burnetii antigen. Tetracycline, with or without lincomycin or cotrimoxazole, was used in nine patients, and one patient received cotrimoxazole as as the sole antibiotic agent. Optimal duration of therapy is unknown. In one patient, relapse followed when treatment was stopped after 18 months. Valve replacement was necessary in five patients, because of hemodynamic problems. Five patients died, and the means survival is 36 months with a range of five to 66 months. We suggest that Q fever endocarditis is frequently missed, and we recommend clinicians to consider the diagnosis in all cases of culture-negative endocarditis.

Chronic Q fever endocarditis

Eight patients with chronic Q fever endocarditis were treated with tetracycline for up to 40 months. In addition, five of these patients received co-trimoxazole. Six patients had prosthetic valves. Two patients who had Q fever endocarditis on their native valves required valve replacement because of haemodynamic difficulties: in only one did the Q fever endocarditis contribute to the haemodynamic difficulty. One patient died. It is suggested that medical treatment is continued until clinically and haematologically there is no evidence of endocarditis and the Q fever phase 1 antibody titre is less than 200. No recurrence of Q fever endocarditis has been detected in three of our patients who have now stopped treatment.

The chest film findings in 'Q' fever--a series of 35 cases

Thirty-five cases of 'Q' fever have been admitted and confirmed serologically over the past 20 years. Thirty-two of these cases had chest films on admission, and lung changes were present in 87%. The lung changes were: 1. Multiple round segmental consolidations, 5--10 cm in diameter, of ground glass density and usually situated in the lower lobes. 2. Linear atelectasis. 3. Lobar or partial lobar consolidation, with some loss of volume in the affected lobe. 4. A slight pleural reaction in a few cases. 5. Some cases had background emphysema of the lungs. All the lesions tended to be slow to clear. The resolution time was from 10 to 70 days, with an average time fo 30 days. Some of the segmental lesions became small, round and dense during resolution. The 35 cases were almost exclusively in males. The finding of a single or multiple round segmental opacities of ground glass density, as described, especially with linear atelectasis, was found to be good evidence that the patient had 'Q' fever. The point is made that the admission chest film is in some cases a very useful early pointer to the diagnosis. This allows specific chemotherapy to be started before the serological results have come back. Plate atelectasis was helpful as a distinguishing feature from primary atypical pneumonia.

The epidemiology of Q fever

Q fever was first described in Australia and has since been reported from many countries. Rickettsia burneti infects numerous species of mammals and has been isolated from ticks. Infected cattle, sheep and goats remain healthy but excrete the organism, which is present in high concentration in products of conception and survives in dust for long periods. The ways in which humans may become infected are considered. Many of these infections do not cause symptoms, but some are fatal and the prevention of this disease remains a challenge.

The occurrence of Coxiella burnetii in North-Western England and North Wales. A report from five laboratories of the Public Health Laboratory Service

A retrospective survey of Coxiella burnetii infection in North-Western England and North Wales was made in five Public Health Laboratories for the years 1962–6 inclusive. Groups of the normal population and of persons occupationally exposed to infection were tested for the presence of antibody and the incidence of infected milk was investigated in seven counties.

Forty-one cases of C. burnetii infection were diagnosed in 7046 patients investigated serologically for the presence of viral and rickettsial antibodies. In just over a quarter of the patients there was evidence of occupational hazard or a history of drinking raw milk. The remainder gave no relevant history.

We would like to express our thanks to Dr C. M. Patricia Bradstreet of the Standards Laboratory, Colindale, for the supply of antigen, and to the numerous clinicians who allowed us access to their case records.