ABSTRACT. In dogs, embryo transfer (ET) techniques such as induciton of excessive ovulation and synchronization of estrus have not progressed well. Therefore, using embryos at various developmental stages, ET was investigated in dogs from a beagle colony in which the ovulation days were close, as estimated by the progesterone level. Embryos were recovered 8-11 days after ovulation (4-9 days after mating) by excising the oviducts and uteri (excision method) in 16 animals and by surgical flushing of the uteri at laparotomy (surgical method) in 3 animals. In 24 dogs with -4 to +2 days of difference in the timing of ovulation between donor and recipient dogs, 1-10 embryos at the 8-cell to blastocyst stages were transferred per animal. The mean embryo recovery rate by the excision method (97.1%) was significantly higher than that by the surgical method (42.5%) (p<0.01). Twelve (57.1%) of 21 animals with -1 to +2 days difference in ovulation day became pregnant after the transfer of 8-cell to blastocyst stage embryos. Although 3 dogs with -4 to -2 days of difference of ovulation day underwent ET of morula or compacted morula, none of these dogs became pregnant. The mean ratio of the number of newborns to the number of transferred embryos was only 51.9%. The mean duration of the period between ovulation and delivery in the pregnant recipients was 65.8 days, which tended to be longer than that in natural mating. These results demonstrate that pregnancy can be induced by ET at the 8-cell to blastocyst stage in dogs with -1 to +2 days difference in ovulation day.

ABSTRACT. The prevalence of hepatitis E virus (HEV) infection in wild boars and pigs in Gunma Prefecture, Japan, was serologically and genetically examined. The positive detection rates of anti-HEV IgG and HEV RNA in the wild boars were 4.5% (4/89) and 1.1% (1/ 89), whereas those in the pigs were 74.6% (126/169) and 1.8% (3/169), respectively. The positive rates of anti-HEV IgG and HEV RNA on the 17 pig farms in the present study ranged from 20% to 100%, respectively. One male wild boar approximately 5 years of age was positive for HEV RNA but was negative for anti-HEV IgG. Three pigs from 2 farms were positive for HEV RNA; 2 of these pigs were negative for HEV IgG, and the other was positive. A phylogenetic analysis revealed that all of the HEV ORF1 genes detected in the present study belonged to genotype III. In Gunma Prefecture, HEV is highly prevalent and widespread, and uncooked wild boar and pig meat may have the potential to transmit HEV to humans. KEY WORDS: hepatitis E virus, Japan, swine, wild boar.J. Vet. Med. Sci. 71(1): 21-25, 2009 Hepatitis E virus (HEV), which belongs to the genus Hepevirus, is the causative agent of hepatitis E. Hepatitis E infection has been found in many developing countries in Asia, Africa and Latin America, where the disease is an important public health concern [15]. HEV is primarily transmitted by the fecal-oral route such as in waterborne epidemics.Recent studies have suggested that HEV is divided into 4 genotypes designated as G I, G II, G III, and G IV [17]. The HEV infections in Asia and Africa are mainly caused by G I, and the majority of the GII infection have been reported in Mexico and Nigeria. On the other hand, only a single case of infection with GIII or GIV has been described in the United States, European counties, Argentina, Taiwan and China [17,21,22]. In Japan, most imported cases with G I have derived from epidemic areas such as Asia and Africa [2]; however, G III or G IV has also been detected in acute hepatitis patients who have never traveled to HEV epidemic areas [6,8,13,14,20,21,24,29]. These patients often have a history of consuming uncooked wild boar (Sus scrofa leucomystax) and sika deer (Cervus nippon) meat and liver [5,27,28]. Also, HEV strains belonging to G I, G III or G IV have been detected in Japanese patients with sporadic acute or fulminate hepatitis E [8, 9, 19-22, 24, 31]. In addition, Yazaki et al. [31] reported that HEV RNA has been detected in 2% (7/363 packages) of sold pig liver on the market by reverse transcription-polymerase chain reaction (RT-PCR).In Japan, it has been suggested that the transmission route of HEV remains unclear in approximately 60% of infected patients [1]; zoonotic food-borne transmissions account for 30%, imported infection accounts for 8% and blood transfusion is responsible for 2%. In Gunma Prefecture, Japan, approximately 3,000 wild boars are annually slaughtered for meat [unpublished data], and the number of breeding pigs in the prefecture was approximately 6 million in 2005. According to the Gunma Pre...

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BackgroundDengue is a common mosquito-borne viral disease epidemic especially in tropical and sub-tropical regions where water sanitation is not substantially controlled. However, dengue epidemics sometimes occur in non-tropical urban cities with substantial water sanitary control. Using a mathematical model, we investigate what conditions can be important for a dengue epidemic to occur in an urban city such as Tokyo, where vectors are active only in summer and there are little number of vectors around hosts.MethodsThe model, which is a modified Ross-Macdonald model, consists of two sets of host-vector compartments. The two sets correspond to high-risk and low-risk areas, and only hosts can move between them. Assuming that mosquitoes have constant activity for only 90 days, we assess five potential countermeasures: (1) restricted movement between the two areas, (2) insecticide application, (3) use of repellents, (4) vector control, and (5) isolation of the infected.ResultsThe basic reproduction number R0 and the cumulative number of infected hosts for 90 days are evaluated for each of the five countermeasures. In the cases of Measures 2–5, the cumulative number of the infected for 90 days can be reduced substantially for small R0 even if R0>1. Although R0 for Measure 1 monotonically decreases with the mobility rates, the cumulative number of the infected for 90 days has a maximum at a moderate mobility rate. If the mobility rate is sufficiently small, the restricted movement effectively increases the number density of vectors in the high-risk area, and the epidemic starts earlier in the high-risk area than in the low-risk one, while the growth of infections is slow.ConclusionsMeasures 2–5 are more or less effective. However, Measure 1 can have the opposite effect, depending on the mobility rates. The restricted movement results in the formation of a kind of core population, which can promote the epidemic in the entire population.

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From 125 bovine fecal samples at a slaughterhouse, 1,125 strains of Enteropathogenic Escherichia coli (EPEC) were isolated. Seventy-seven isolates from 26 samples were of EPEC, and 32 from 8 samples were of serovar O157. The reverse latex agglutination revealed that 24 of 32 O157 strains produced verocytotoxin. The Verocytotoxin-producing Eschrichia coli (VTEC) isolates were sensitive to eight drugs except erythromycin, cefalothin, and sulfadimethoxine. However, several strains resisted to ampicilin, tetracyclin, kanamycin, and streptomycine.