Epidemiology of Avian Infectious Laryngotracheitis with Special Focus to South America: an update

ABSTRACT Avian Infectious laryngotracheitis (AILT) is a respiratory tract disease of great importance because it causes significant economic losses in the poultry industry around the world. It is caused by a Gallid herpesvirus type 1, a member of the genus Iltovirus. The target system for Avian Infectious Laryngotracheitis virus (AILTV) infections is the respiratory system, and the main organ in which the virus remains latent is the trigeminal ganglia. However, the virus has demonstrated tropism for other organs besides the respiratory tract. The main transmission routes are ocular and respiratory. Infected birds with clinical symptoms are main sources of transmission, but birds with latent infections, litter, and contaminated fomites may also transmit the virus. Clinical signs usually appear 6-12 days after natural exposure and may be moderate or severe. The causative agent of this disease can be propagated in chorioallantoic membrane (CAM) of developing chicken embryos and replicate in mature chicken kidney cells, as well as in a variety of epithelial chick embryo cells, such as kidneys, liver and lungs. There are several procedures for the diagnosis of ILT such as the observation of clinical signs, the detection of gross and histopathological lesions, and the use of molecular techniques, including RFLP, polymerase chain reaction (PCR), real-time PCR, and loop-mediated isothermal amplification. Vaccination with different types of vaccine provides a good expectation on disease control, such as vaccines produced in chicken-embryo-origin (CEO), tissue-culture-origin (TCO), and recombinant vaccines. However, in endemic areas, biosecurity measures and best management practices are important for the control of the disease. It is distributed worldwide and, in South America, it has been reported in Brazil, Peru, Ecuador, Bolivia, and Argentina causing great economic losses

Occurrence of infectious Laryngotracheitis Virus (ILTV) in 2009-2013 in the State of São Paulo - Brazil

Infectious laryngotracheitis is a very important respiratory disease because it causes significant economic losses in the poultry industry. The target of ILTV infections is the respiratory system, and the main organ in which the virus remains latent is the trigeminal ganglia. However, the virus has demonstrated tropism for other organs as well. The present study was conducted to determine the presence of Infectious Laryngotracheitis Virus (ILTV) in the state of São Paulo. Samples submitted to LABOR- USP during the last four years (2009-2013) analyzed by a nested/PCR technique. Out of the 682 samples from layers tested for LTIV, 12.46 % were positive, and derived from in both traditional (trachea and trigeminal ganglion) and untraditional (cecal tonsils, digestive tract and kidneys) organs utilized for ILTV diagnosis. The present work showed that ILTV is circulating in commercial layer flocks in São Paulo State, and that the LTIV is present in other organs in addition to the respiratory tract and trigeminal ganglion; however, it was not determined if the circulating virus is a vaccinal or field strain

Detection by Rt-Pcr and Molecular Characterization of Tremovirus A Obtained from Clinical Cases of Avian Encephalomyelitis (AE) Outbreaks in Brazil

ABSTRACT This study determined the presence of Tremovirus A as the possible agent related to Avian Encephalomyelitis in broiler chicks from the states of São Paulo (SP) Paraná (PR), Goiás (GO), Santa Catarina (SC) and Rio Grande do Sul (RS), between the years 2006 and 2015. Samples of the nervous, digestive, respiratory, immune, and renal systems, plus muscular organs from broiler chicks with neurological problems such as ataxia and muscle tremors, and four (4) commercial vaccines as positive control, were tested by reverse-transcriptase (RT-PCR) amplification and DNA sequencing. A highly conserved region (P1) of the viral genome, was used to amplify a segment which encodes a structural protein VP4. Out of 112 samples, 46 were positive (42%) for Tremovirus A, that was identified in the nervous, digestive, respiratory, renal and immune systems. The phylogenetic analysis clustered together the nucleotide sequences of the 46 samples, the four commercial vaccine strains and the reference sequence of Calnek strain obtained from the GenBank. According to these results, we conclude that the presence of Tremovirus A in these Brazilian chicken flocks distributed in all states was due to flaws in the biosecurity measurements

Molecular Diagnostic of Chicken Parvovirus (ChPV) Affecting Broiler Flocks in Ecuador

ABSTRACT Enteric diseases affect poultry and cause important economic losses in many countries worldwide. Avian parvovirus has been linked to enteric conditions, such as malabsorption and runting-stunting syndrome (RSS), characterized by diarrhoea, and reduced weight gain and growth retardation. In 2013 and 2016, 79 samples were collected from different organs of chickens in Ecuador that exhibited signs of diarrhea and stunting syndrome, and analysed for the presence of chicken parvovirus (ChPV). The detection method of ChPV applied was Polymerase Chain Reaction (PCR), using primers designed from the conserved region of the viral genome that encodes the non-structural protein NS1. Out of the 79 samples, 50.6% (40/79) were positive for ChPV, and their nucleotide and amino acid sequences were analysed to determine their phylogenetic relationship with the sequences reported in the United States, Canada, China, South Korea, Croatia, Poland, Hungary, and Brazil. Strong similarity of nucleotide and amino acid sequences among all analyzed sequences and between the analysed and reference sequences was demonstrated, and the phylogenetic analysis clustered all the sequences within the same group, demonstrating a strong relation between the studied strains and the reference chicken parvovirus strains

Genetic models

Genetically altered rat and mouse models have been instrumental in the functional analysis of genes in a physiological context. In particular, studies on the renin-angiotensin system (RAS) have profited from this technology in the past. In this review, we summarize the existing animal models for the protective axis of the RAS consisting of angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7)(Ang-(1-7), and its receptor Mas. With the help of models with altered expression of the components of this axis in the brain and cardiovascular organs, its physiological and pathophysiological functions have been elucidated. Thus, novel opportunities for therapeutic interventions in cardiovascular diseases were revealed targeting ACE2 or Mas