A total of 65 cases of Creutzfeldt–Jakob disease with a history of cadaveric dura transplantation in Japan were analysed to clarify the epidemiologic features of such patients and to explore whether other such patients will appear in the future. The age at transplantation averaged 44·4 years with a standard deviation of 14·4 years. The age at onset had an average of 53·0 years with a standard deviation of 14·1 years. The shortest latent period was 14 months, and the longest was 218 months with an average of 103·1 months and a standard deviation of 49·9 months. From the relationship between the calendar year at transplantation and the latent period, other such patients will appear in the near future. The current data suggested that several patients with Creutzfeldt–Jakob disease will occur from those receiving cadaveric dura mater grafts in the near future.

Control programmes have reduced the prevalence of Bancroftian filariasis in Thailand to low levels. Recently, there has been an influx of more than one million Myanmar immigrants into urban centres of Thailand. The prevalence of patent Wuchereria bancrofti infection in these immigrants (2–5%) has prompted concern in the public health community that the potential now exists for a re-emergence of Bancroftian filariasis in Thailand. It is possible that an urban cycle of transmission could become established. The Myanmar immigrants are infected with the nocturnal periodic (urban) type W. bancrofti for which Culex quinquefasciatus serves as the main vector. The Thai strains of Cx. quinquefasciatus have never been reported to transmit Bancroftian filariasis. Our results of feeding experiments demonstrated that the Thai Cx. quinquefasciatus are permissive for the development of Myanmar W. bancrofti to infective third-stage larvae thus establishing the potential for establishing an urban cycle of transmission in Thailand. We also adapted the SspI repeat PCR assay for the identification of infective mosquitoes that was capable of detecting a single infective stage larvae in a pool of 100 mosquitoes.

We studied the seroprevalence of three viruses (mouse cytomegalovirus (MCMV), minute virus of mice (MVM), and mouse parvovirus (MPV)) in house mice (Mus domesticus) in 1995–7. In the first year average mouse density was less than 1 mouse/ha. From November 1995 to May 1996 the population increased at an average rate of 7% per week, a doubling time of about 10 weeks. From August 1996 to May 1997 the population increased at an average rate of 10% per week, a doubling time of about 7·5 weeks. From a peak around 250 mice/ha in May 1997, the mouse population fell 19% per week to 5 mice/ha in October 1997. The seroprevalence for all three viruses varied dramatically over time. MCMV had the highest seroprevalence (61·7%), followed by MVM (8·5%) and MPV (18·4%). Time series data indicated that MCMV spread rapidly through the population of mice once trap success was greater than 14% (40–100 mice/ha). By contrast MVM and MPV seroprevalence occurred with a 2–3 month and 3–4 month time lag, respectively. The current study supports the contention that MCMV would be a good carrier for an immunocontraceptive vaccine for controlling field populations of mice.

In this work, we applied the random amplified polymorphic DNA (RAPD) technique to evaluate the genetic diversity in Photobacterium damselae subsp. piscicida (formerly Pasteurella piscicida), an important pathogen for different marine fish. Regardless of the oligonucleotide primer employed, the 29 isolates of Ph. damselae subsp. piscicida tested were separated into two groups, the RAPD-PCR analysis differentiated the European strains from the Japanese strains. The similarity between both groups estimated on the basis of the Dice coefficient was 75–80%. These results show that European and Japanese isolates of Ph. damselae subsp. piscicida, regardless of their host fish species, belong to two different clonal lineages. Our findings also indicate that RAPD profiling constitutes a useful tool for epidemiological studies of this fish pathogen.

Partial nucleotide sequence at the 3′ end of 1D (VP1-encoding) gene of 90 foot-and-mouth disease virus type O isolates recovered from field outbreaks in India between 1993–9 were determined. The sequences were compared with each other and reference viruses. The published sequences of 15 type O isolates recovered from different parts of Asia and one isolate (O1BFS) from Europe and one from Egypt (O1/Sharquia/Egypt/72) were also included in the analysis for comparison. On the basis of phylogenetic analysis the viruses could be grouped into four distinct genotypes (genotypes I–IV). All 90 isolates from India were genotype-I, as were the reference isolates from Bangladesh, China, Egypt, Iran, Saudi Arabia, Syria and Turkey. Genotype-I isolates were further subdivided into 16 sub-genotypes. The Indian isolates were found to be extremely heterogeneous in nature and clustered into 12 different genetic groups. In genotype-I, the nucleotide sequence difference seen between the isolates was 0–11·6%, while among the Indian isolates it is 0–8·8%. Viruses of similar genetic groups are circulating in India, Bangladesh and countries of the Middle East. Genotype-II and -III are represented by isolates from Lebanon (O1/South Lebanon) and Europe (O1-BFS), respectively. Genotype-IV is formed by isolates from China, Hong Kong and Taiwan. The present study reveals the occurrence of viruses belonging to multiple genetic groups over a short period of time and persistence of single genetic group in the same geographical area over several years. This is consistent with the endemic nature of the disease in the country.

Escherichia coli O157 isolates from cattle in Japan (n = 91) and in the USA (n = 415) were compared by pulsed-field gel electrophoresis of endonuclease-cleaved genomic DNA, location of the stx genes and bacteriophage typing. Three isolates from cattle in Japan with high similarity to isolates from cattle in the USA were found. Isolates from cattle farms in Japan and the USA may share a common source.

Epidemiol. Infect.124 (2000), 61–7

Occurrence ofClostridium perfringensβ2-toxin amongst animals, determined using genotyping and subtyping PCR assays

Page 61, Summary, line 7, should read:

‘… and the gene encoding β2-toxin was …’