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• Biological Characteristics of Cassava Witches’ Broom Disease Related to Phytoplasma in Dongnai Province

  Nguyen Duc Thanh, Mai Van Quan, Ngo Gia Bon, Nguyen Huu Hy, Ha Viet Cuong, Trinh Xuan Hoat

  Date Received: 04-04-2014 / Date Accepted: 09-06-2014

   Abstract PDF (VIETNAMESE)

  In Vietnam, cassava witches’ broom is an important disease in cassava production. Phytoplasma, 16SrI group-‘Candidatus Phytoplasma asteris’ is the causal agent associated with cassava witches’ broom disease. In this study, leafhopper species were collected by using light traps. Total DNA was extracted from the insect species and the symptomatic plants. Nested polymerase chain reaction assay was used to detect the presence of phytoplasma. Amplification of a fragment 1100 base pair 16S rDNA gene confirmed that insect bodies were infected by the phytoplasma. Restriction fragment length polymorphism analysis using EcoRI and HaeIII endonucleases revealed the insignificant difference between the test samples. Cassava witches’ broom disease is transmitted by cutting through vegetative propagation using diseased plants under screenhouse or field conditions. Whitefly (Aleurodicus dispersus), mealybug (Paracoccus marginatus) and red mite (Tetranychus urticae) do not transmit phytoplasma although they fed on cassava plant in the field.

• Determining the Prevalence of Porcine Adenovirus (PAdV) in PigsRaisedin some Provinces in the North of Vietnam

  Le Van Truong, Huynh Thi My Le, Dang Huu Anh, Nguyen Van Giap, Mai Thi Ngan, Vo Van Hieu, Trinh Huong Ly, Le Van Phan

  Date Received: 31-12-2022 / Date Accepted: 27-03-2023

   Abstract PDF (VIETNAMESE)

  Porcine adenovirus (PAdV) is the causative agent of diarrhea in piglets aged one to four weeks. Among the three species of adenoviruses (AdVs) that cause disease in pigs, A, B, and C, six serotypes have been identified through neutralization methods. Our study aimed to determine the prevalence of PAdV in pigs raised in Hanoi and its surrounding areas. One hundred and forty fecal samples were collected from piglets exhibiting diarrhea symptoms and subjected to DNA extraction. Nested PCR was then used to detect PAdV in the samples. Positive PCR samples were purified and sequenced. The results showed that the nested PCR method was effective in diagnosing PAdV causing diarrhea in pigs, with 43.57% (61/140) of the samples testing positive. Ten out of fourteen (71.43%) farms showed a prevalence of PAdV. The sequencing results of the PAdV hexon gene segment of the positive samples identified six strains of PAdV circulating in Vietnam, including PAdV-8, PAdV-25, PAdV-26, PAdV-28, PAdV-33, and PAdV-34. The molecular epidemiological analysis of PAdV also revealed that all six strains isolated in Vietnam belonged to PAdV serotype 3, a species of Adenovirus A, genus Mastadenovirus.