Molecular methods indicate lack of spread of Acarapis woodi introduced to honey bees in western Norway.

The tracheal mite, Acarapis woodi, may be one of many factors contributing to the decline in honey bee (Apis mellifera) populations. Databases on the widespread distribution of A. woodi exist, but the data seem patchy. Norway is not listed as being infested, although there have been at least two separate introductions of the parasite. Investigations in 2003, 2006, and 2009 using standard microscopy methods indicated persistence of A. woodi in honey bees in this region. In 2013, we conducted another survey. Samples were sent in from 335 beehives belonging to 39 apiaries, and all were asked to complete a questionnaire. Analysis for A. woodi in the submitted samples was by PCR, with sequencing of positive results. The results described in this article indicate that this parasite still persists in some apiaries in this region, but at a low, and possibly decreasing, level, with positive results obtained from just two (5.1%) of the apiaries. Of the 17 beekeepers that answered the questionnaire, none reported symptoms of infestation with A. woodi. Sequencing of PCR products indicated a difference between the two A. woodi isolates. Our results were generally encouraging regarding the apparent lack of spread of A. woodi, within the County. Furthermore, the sequencing results may indicate two separate introductions rather than spread. Nevertheless, the scarcity of data, the vulnerability of honey bee populations globally, and the potential contribution of this parasite to reduced survival, indicate that the situation should be continued to be monitored. In addition, Norwegian beekeepers should be made aware of, and follow, restrictions regarding import and transport of bees, both nationally and internationally.

Dirofilaria repens infection in a dog imported to Norway.

Dirofilaria repens infection was diagnosed in a dog that had been imported to Norway from Hungary three years previously. The dog was a four-year-old castrated male mixed-breed dog and presented for examination of two masses on the right thoracic wall. Fine needle sampling from the subcutaneous nodules and subsequent cytological examination revealed a high number of microfilariae and a pyogranulomatous inflammation. At re-examination approximately 3 weeks later, both masses had apparently disappeared spontaneously, based on both inspection and palpation. However, examination of peripheral blood by a modified Knott's test revealed a high number of unsheathed microfilariae with mean length of 360 µm and mean width of 6-7 µm, often with the classic umbrella handle appearance of D. repens. Polymerase chain reaction and sequencing confirmed the D. repens diagnosis. Subcutaneous dirofilariosis caused by D. repens is probably the most common cause of human zoonotic dirofilariosis in Europe, but currently is rarely encountered in northern countries such as Norway. However, travelling, import and relocation of dogs have increased, and thus the geographical range of these parasites is likely to increase from traditionally endemic southern regions. Increasing numbers of autochthonous cases of D. repens infections in dogs have been reported in eastern and central Europe. Although infection with D. repens often induces only mild signs or subclinical infections in dogs, they nevertheless represent a reservoir for zoonotic transmission and thus a public health concern, and, in addition, due to the long prepatent period and the high frequency of subclinical infections or infections with unspecific clinical signs, could easily be missed. Lack of experience and expectation of these parasites may mean that infection is underdiagnosed in veterinary clinics in northern countries. Also, predicted climate changes suggest that conditions in some countries where this infection is currently not endemic are likely to become more suitable for development in the intermediate host, and thus the establishment of the infection in new areas.

A water contamination incident in Oslo, Norway during October 2007; a basis for discussion of boil-water notices and the potential for post-treatment contamination of drinking water supplies.

Over a 5 day period in October 2007 a boil-water notice was served on the majority of Oslo, capital city of Norway, as a result of a combination of bacteriological findings (coliforms, intestinal enterococci, and E. coli), and very low numbers of Cryptosporidium oocysts and Giardia cysts in 10 L water samples taken from the water distribution network. The water source had been regularly monitored for these parasites and generally found to be negative. Over 460,000 residents were affected by the boil-water notice, as were many thousands of businesses. Despite an extensive outbreak of waterborne giardiasis in Bergen, Norway during 2004/2005, occurrence of parasites in Norwegian drinking water supplies has apparently continued to be considered to be of minimal relevance by Norwegian health authorities. Here we describe the background and occurrence of the episode in Oslo, including the species of Cryptosporidium detected, and use this event, in conjunction with incidents from other countries, as a basis to discuss the following issues: (1) under which circumstances should the occurrence of Cryptosporidium oocysts and Giardia cysts in water supplies trigger the issue of a boil-water notice, and (2) the possibilities and probabilities of post-treatment contamination events in the water distribution network.