Mass mortality of cultured white shrimp in southern Taiwan was diagnosed as an outbreak of Taura syndrome (TS). From late 1998 to early 1999, 90% of the shrimp ponds were abandoned at 30 to 45 d after stocking post larvae from Ecuador and elsewhere. The shrimp began to die within 2 to 3 d after they stopped feeding. There were no other gross signs, except that some affected shrimp had reddened tails. Histologically, multifocal necrosis of the cuticular epithelium was the main lesion. The necrotic foci contained pyknotic and karyorrhectic nuclei, and many lightly and densely stained intracytoplasmic and intercellular, spherical inclusions.

Prior to the emergence of koi herpesvirus (KHV), cyprinid herpesvirus (CHV) was the only pathogen known to cause herpesviral diseases in common carp and koi Cyprinus carpio 1,2). In 1998, a newly recog nized virus, KHV was isolated in Israel and the USA, and shown to be pathogenic for koi and common carp of all ages. It can cause 80-100% mortality, mainly with se vere hyperplasia and necrosis of gill epithelia and necro sis of other organs3). Later, outbreaks of KHV disease were reported in the United Kingdom, Germany, Japan and were suspected in Indonesia*1,*2,*3,*4) by 2003. Recently, due to the large ca•`277 kbp genome

ABSTRACT. Since March 1997 two strains of foot and mouth disease (FMD) virus have found their way into Taiwan, causing severe outbreaks in pigs and in Chinese yellow cattle. Outbreaks occurred in March 1997 were caused by a pig-adapted virus strain (O/Taiwan/ 97) which did not infect other species of cloven-hoofed animals by natural route. The epidemic spread over the whole region of Taiwan within two months and the aftermath was 6,147 pig farms infected and 3,850,746 pigs destroyed. In June 1999, the second strain of FMD virus (O/Taiwan/99) was isolated from the Chinese yellow cattle in the Kinmen Prefecture and in the western part of Taiwan. By the end of 1999, Chinese yellow cattle were the only species infected and those infected cattle did not develop pathological lesions. Seroconversions of serum neutralization antibody and on non-structural protein (NSP) antibodies were the best indicators for infection in non-vaccinated herds. The infected animals, however, excreted infectious levels of virus to infect new hosts. Based on the detection of the specific antibody to FMD virus, and virus isolation from oesophageal-pharyngeal (OP) fluid samples, ten herds of Chinese yellow cattle located in Kinmen and Taiwan were declared to have been infected. During the period of January to March 2000, however, five outbreaks caused by FMD virus similar to the O/Taiwan/99 virus occurred in four prefectures of Taiwan. The infected species included goats, Chinese yellow cattle and dairy cattle. Those outbreaks have caused high mortality in goat kids under two weeks old and also developed typical clinical signs of infection in dairy cattle.KEY WORDS: Chinese yellow cattle, foot and mouth disease virus, non-structural protein, serotype O, VP1 gene.

ABSTRACT. In an effort to understand the genetic diversity of porcine circovirus type 2 (PCV2) and the prevalence of PCV2 infection in Taiwanese herds, we have sequenced the complete genomes from PCV2-infected specimens and individually measured the antibody tite r against PCV2 from pigs reared in Taiwan between the years 2000 and 2002. A total of 623 specimens originating from pigs display ing varied clinical signs were screened with the polymerase chain reaction (PCR). Results showed that 309 pigs (49.6%) tested positive for PCV2. Eight of the positive specimens were used for the amplification of the complete viral genome. Sequence comparison of the complete genomes indicated that the 8 Taiwanese PCV2 isolates shared 95-99% similarity. Phylogenetic analysis of all 40 PCV2 isolates from North America, Europe, Asia and Taiwan revealed that those isolates were grouped together in one large group containing two minor subgroups. The Taiwanese PCV2 isolates were classified into the two minor subgroups. The prevalence of serum antibodies to PCV2 in pigs was investigated, and results showed that approximately 83.5% of the pigs in Taiwan were seropositive. Finishing pigs possess the highest titers of antibodies, while 9-week-old pigs contained the lowest titers for specific antibodies. Our result s suggest that PCV2 infections have become common in Taiwanese pig farms. KEY WORDS: phylogenetic analysis, polymerase chain reaction, porcine circovirus type 2, seropositive.