A 10-Year Retrospective Study of Inclusion Body Hepatitis in Meat-Type Chickens in Spain (2011-2021).

A surge in fowl adenovirus (FAdV) causing inclusion body hepatitis (IBH) outbreaks has occurred in several countries in the last two decades. In Spain, a sharp increase in case numbers in broilers and broiler breeder pullets arose since 2011, which prompted the vaccination of breeders in some regions. Our retrospective study of IBH cases in Spain from 2011 to 2021 revealed that most cases were reported in broilers (92.21%) and were caused by serotypes FAdV-8b and -11, while cases in broiler breeder pullets were caused by serotypes FAdV-2, -11, and -8b. Vertical transmission was the main route of infection, although horizontal transmission likely happened in some broiler cases. Despite the inconsistent and heterogeneous use of vaccines among regions and over time, the number of cases mirrored the use of vaccines in the country. While IBH outbreaks were recorded year-long, significantly more cases occurred during the cooler and rainier months. The geographic distribution suggested a widespread incidence of IBH and revealed the importance of a highly integrated system. Our findings contribute to a better understanding of FAdV infection dynamics under field conditions and reiterate the importance of surveillance, serological monitoring of breeders, and vaccination of breeders against circulating serotypes to protect progenies.

Prevalence of inclusion body hepatitis (IBH) in Poland from 2010-2014.

This study investigated the prevalence of inclusion body hepatitis (IBH) infections during the past five years (2010-2014) in broiler chicken flocks in Poland. The diagnosis of IBH was based on anatomopathological investigations and histopathological analyzes. IBH was the most prevalent disease in broiler flocks in Poland (10.4%) during this time period, and occurred as a primary infection. The fewest cases of IBH occurred in the summer, suggesting that the temperature may have been a possible stressor that increased susceptibility to IBH. However, over the last 5 years the occurrence of clinical IBH cases in Poland has systematically decreased.

Mouse hepatitis virus infection of the CNS: a model for defense, disease, and repair.

Viral infection of the central nervous system (CNS) results in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences. One of the principal factors that directs the outcome of infection is the localized innate immune response, which is proceeded by the adaptive immune response against the invading viral pathogen. The role of the immune system is to contain and control the spread of virus within the CNS, and paradoxically, this response may also be pathological. Studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV) have provided important insights into how the immune system combats neuroinvasive viruses, and have identified molecular and cellular mechanisms contributing to chronic disease in persistently infected mice.

New hepatitis viruses: are there enough letters in the alphabet?

Testing is now available for five recognised hepatitis viruses (A, B, C, D and E), and molecular technology is uncovering further hepatotropic viruses. An enteric agent isolated from human stool samples and transmitted experimentally to primates is a candidate hepatitis F virus. A provisionally designated blood-borne hepatitis G virus is associated with acute and chronic non-ABCDE hepatitis and has a worldwide distribution. A group of flavi-like viruses, the GB group, also blood borne, has also been reported. The role of two of these viruses, GBV-A and GBV-B, in human viral hepatitis has not been determined, but a third agent, GBV-C, is associated with acute and chronic hepatitis and appears to be a West African variant of hepatitis G. Our current knowledge suggests that the hepatitis alphabet may need to be extended even after inclusion of some of these new viruses.