We present new and revised data for the phocine distemper virus (PDV) epidemics that resulted in the deaths of more than 23 000 harbour seals Phoca vitulina in 1988 and 30,000 in 2002. On both occasions the epidemics started at the Danish island of Anholt in central Kattegat, and subsequently spread to adjacent colonies in a stepwise fashion. However, this pattern was not maintained throughout the epidemics and new centres of infection appeared far from infected populations on some occasions: in 1988 early positive cases were observed in the Irish Sea, and in 2002 the epidemic appeared in the Dutch Wadden Sea, 6 wk after the initiation of the outbreak at Anholt Island. Since the harbour seal is a rather sedentary species, such 'jumps' in the spread among colonies suggest that another vector species could have been involved. We discussed the role of sympatric species as disease vectors, and suggested that grey seal populations could act as reservoirs for PDV if infection rates in sympatric species are lower than in harbour seals. Alternatively, grey seals could act as subclinical infected carriers of the virus between Arctic and North Sea seal populations. Mixed colonies of grey and harbour seal colonies are found at all locations where the jumps occurred. It seems likely that grey seals, which show long-distance movements, contributed to the spread among regions. The harbour seal populations along the Norwegian coast and in the Baltic escaped both epidemics, which could be due either to genetic differences among harbour seal populations or to immunity. Catastrophic events such as repeated epidemics should be accounted for in future models and management strategies of wildlife populations.
Eighty-eight patients with opisthorchiasis were treated with biltricide in an anthropurgic and natural focus of opisthorchiasis in the Altai Territory. A one-day course of drug therapy, in a total dose of 60 mg/kg, was administered. Forty-two patients developed side effects in the course of therapy. Complete elimination of the helminths was achieved in 83 (94.3 +/- 2.3%; p less than 0.05) patients in 6 months after therapy.
Natural tularemia foci of the meadow and steppe type are extremely stable and become active in those years when the most favourable living conditions for rodents appear. For the first time during the last 30 years a great increase in the number of common voles, accompanied by widely spread epizooty covering the whole territory of the Tula region, was observed. House mice, common field mice, harvest mice and black rats were also involved in this epizooty and 235 tularemia patients with all clinical forms of the disease were registered, the pulmonary form of the disease being prevalent. The cases of the disease were observed among both urban and rural population. In spite of a high morbidity rate, no cases of group infection were registered in domestic conditions and among agricultural workers due to the existence of the numerous immune layer among the population. The formation of this layer resulted from planned vaccinal prophylaxis covering, on the average, 86.3% of the rural population of the region.
An Israeli researcher working in Finland with Bank Voles, contracted an infectious viral disease and died. This was a rare event, but it is important to learn about this class of viruses and to be aware of the hazards while working in the field in close contact with wild animals. The virus termed Puumala belongs to the genus Hanta from the Bunyaviridae family. The natural reservoir is rodents, mice, rats and Bank Votes for the Puuamala strain. The disease is termed HFRS (hemorrhagic fever with renal syndrome), is prevalent in Asia and Europe, affecting 200,000 people a year, with 5-15% percent mortality (although in Finland mortality rate is 0.1%). The New World strains cause HPS (hemorrhagic pulmonary syndrome) affecting 200 people a year with 40% mortality. Virus is present in all rodents excretions, and route of infection is by aerosols, hand to mucus membranes contamination, by rodents bites and by contaminated food or water. More than 226 work related infections were documented. Treatment with Ribavirin helps in HFRS but not in HPS. The virus is stable in the environment for long periods, and research must be carried out at biosafety level 3. Working outdoors in rodent infested area, should be carried out using protective clothing, gloves, googles and face mask whenever aerosol producing tasks are performed. Both indoor and outdoor, it is important to adhere to self-hygienic procedures, especially hand washing.