An investigation into aflatoxin M 1 in slaughtered fattening pigs and awareness of aflatoxins in Vietnam.

BACKGROUND: Aflatoxin M1 (AFM1) is a hydroxylated metabolite formed after aflatoxin B1 (AFB1) is consumed by humans and animals; it can be detected in urine, milk and blood. It is well recognized that AFB1 is toxic to humans and other animals. The International Agency for Research on Cancer (IARC) classifies aflatoxins as group 1 carcinogens and AFM1 as group 2B carcinogen. The main objective of this study was to evaluate the exposure of pigs to aflatoxins as well as to assess the public awareness of aflatoxins among people in five provinces in Vietnam. RESULTS: A total of 1920 urine samples were collected from slaughterhouses located in five provinces. Overall, the positive rate of AFM1 was 53.90% (95% confidence interval 51.64-56.15) using a cut-off of 0.15 µg/kg (range: limit of detection to 13.66 µg/kg, median: 0.2 µg/kg and mean: 0.63 µg/kg). A total of 252 people from the general population were interviewed from 5 provinces, and overall 67.86% reported being aware of aflatoxins. We also found that men and more highly educated had significantly increased awareness of aflatoxins compared to the females and primary/secondary school group. The respective odds ratios (ORs) were as follows: "male" group (OR: 2.64), "high school educated" group (OR: 3.40) and "college/university or more educated" group (OR: 10.20). CONCLUSIONS: We can conclude that pigs in Vietnam are exposed to aflatoxins to varying degrees, and there may be a risk that pork products could contain AFM1. Further investigation is needed into the possible health impacts as well as to aid in establishing regulations for animal feed to reduce the health impacts in humans and animals.

Sero-prevalence of specific Leptospira serovars in fattening pigs from 5 provinces in Vietnam.

BACKGROUND: Leptospirosis is a zoonotic bacterial disease with a worldwide distribution. In Vietnam, leptospirosis is considered endemic. In pigs, leptospirosis can result in reproductive problems (such as abortion and infertility) which lead to economic loss. In addition, transmission to people presents a public health risk. In Vietnam, few national studies have been conducted on sero-prevalence of leptospirosis in pigs. The main objective of this study was to evaluate the sero-prevalence and incidence of presumptive infective leptospira serovars in fattening pigs from 5 provinces in Vietnam. RESULTS: Blood samples from fattening pigs were randomly collected at slaughterhouses. We collected 1959 sera samples from 5 provinces (Son La, Hanoi, Nghe An, Dak Lak and An Giang) between January and early June 2016. The microscopic agglutination test (MAT) was used to identify the serogroups/serovars. Overall, the sero-prevalence was 8.17% (95% CI: 6.99-9.47) and serovar Tarassovi Mitis (2.19%) had the highest prevalence followed by Australis (1.94%), Javanica (1.68%) and Autumnalis (1.17%) using a cutoff (≥ 1:100). The sero-prevalence among female pigs (5.28%, 95% CI: 3.94-6.93) was slightly higher than among male pigs (4.88%, 95% CI: 3.51-6.58), but this difference was not statistically significant. CONCLUSIONS: Leptospirosis in pigs may be a useful indicator of the human/animal burden in Vietnam and a risk assessment tool. The presence of some of the identified serovars suggests that wildlife may play an important role in the transmission of leptospirosis to domesticated pigs in Vietnam. Therefore, strengthened monitoring and surveillance systems are needed to better understand the epidemiology of the disease and prevent or reduce infection in humans and animals.

Mechanism of the antiviral effect of hydroxytyrosol on influenza virus appears to involve morphological change of the virus.

Hydroxytyrosol (HT), a small-molecule phenolic compound, inactivated influenza A viruses including H1N1, H3N2, H5N1, and H9N2 subtypes. HT also inactivated Newcastle disease virus but not bovine rotavirus, and fowl adenovirus, suggesting that the mechanism of the antiviral effect of HT might require the presence of a viral envelope. Pretreatment of MDCK cells with HT did not affect the propagation of H9N2 virus subsequently inoculated onto the cells, implying that HT targets the virus but not the host cell. H9N2 virus inactivated with HT retained unaltered hemagglutinating activity and bound to MDCK cells in a manner similar to untreated virus. Neuraminidase activity in the HT-treated virus also remained unchanged. However, in the cells inoculated with HT-inactivated H9N2 virus, neither viral mRNA nor viral protein was detected. Electron microscopic analysis revealed morphological abnormalities in the HT-treated H9N2 virus. Most structures found in the HT-treated virus were atypical of influenza virions, and localization of hemagglutinin was not necessarily confined on the virion surface. These observations suggest that the structure of H9N2 virus could be disrupted by HT.