Luis Fabian Nuñez Naranjo

• Professor
• Universidad de Las Américas

In the poultry industry, intestinal diseases can lead to significant economic losses due to diarrhea, weight loss and mortality, often linked to viral infections. Chicken astrovirus (CAstV), avian nephritis virus (ANV), infection bronchitis virus (IBV), avian rotavirus A (AvRVA) and avian orthoreovirus (ARV) are key pathogens on this disease includ...

Background Chicken meat production has expanded considerably on a global scale due to its ease of production compared to other species. As a result, the prevalence of avian viruses has grown. Chicken astrovirus (CAstV), an RNA virus with roughly 7 kb in length that is disseminated globally and exhibits both horizontal and vertical transmission, is...

Canine Astrovirus (CaAstV) part of the Astroviridae family and genus Mamastrovirus, is a linear RNA virus with a genome of approximately 6.6 kb with three open reading frames (ORF): ORF1a and ORF1b, which code for the most conserved non-structural proteins, and ORF2, which code for the capsid protein, the most variable region of the genome. This pa...

Escherichia coli (E. coli), especially the Shiga toxin-producing O157:H7 strain, poses severe health risks. In rural Ecuador, raw milk consumption heightens contamination risks. This study analyzed 633 raw milk samples from Pichincha and Manabí to assess E. coli O157:H7 prevalence. The samples were enriched using BHI broth, and then specific cultur...

Canine parvovirus (CPV-2) is a highly contagious virus in canines, and it is mostly spread by touching infected feces. Dogs of all ages can catch it, but puppies are more likely to suffer from it. Severe signs include vomiting, diarrhea with blood, feeling tired, and not drinking enough water. There are three different types of the original CPV-2 t...

Background and Aim Viral gastroenteritis in canines is primarily caused by the canine parvovirus 2 (CPV-2). Infections by this virus can cause severe consequences in dogs, such as fever, vomiting, diarrhea, septicemia, systemic inflammation, and immunosuppression. Therefore, the mortality rate of persistent infections caused by this virus is signif...

Background and Aim Fowl adenovirus (FAdV) is the etiological agent of inclusion body hepatitis (IBH) and hepatitis-hydropericardium syndrome (HHS) in poultry. It is also detected in chickens with runting and stunting syndrome (RSS). FAdV has been detected worldwide, and genotypes 8a, 8b, and 11 have been identified in chickens with enteric problems...

Chicken Parvovirus (ChPV) belongs to the genus Aveparvovirus and is implicated in enteric diseases like runting–stunting syndrome (RSS) in poultry. In RSS, chicken health is affected by diarrhea, depression, and increased mortality, causing significant economic losses in the poultry industry. This study aimed to characterize the ChPV genomes detect...

Respiratory RNA viruses such as Infectious bronchitis virus (IBV) and Avian metapneumovirus (aMPV), which are characterized by generating both respiratory damage and adverse effects on reproductive organs, affect poultry production economically due to high mortality rate and decrease in egg production and quality. Particularly, aMPV has three genot...

Simple Summary Enteric viruses are the main cause of gastrointestinal disease in dogs. Canine astrovirus (CaAstV) is an enteric virus that causes severe dehydration, diarrhea and vomiting, among other gastrointestinal symptoms. The present study is based on the design, standardization, and execution of a rapid and sensitive qPCR protocol using SYBR...

IDS presented pathognomonic dilatation of the jejunum up to Meckel's diverticulum.IDS caused weight loss, decreased egg production, and increased culling and mortality.Chicken parvovirus (ChPV) was consistently detected through PCR assays.Chicken megrivirus (ChMV) was consistently detected through viral metagenomics.

Parvovirus infection affects several animal species, especially young animals. In birds, parvovirus infection has been described in Muscovy ducks, turkeys, and chickens, all of which had enteric diseases characterized by diarrhea. Chicken parvovirus (ChPV) has been detected in poultry around the world in animals affected by enteric problems, showin...

Background Enteric viruses are among the most prominent etiological agents of Runting-Stunting Syndrome (RSS). The Avian Nephritis Virus (ANV) is an astrovirus associated with enteric diseases in poultry, whose early diagnosis is essential for maintaining a good poultry breeding environment. ANV is an RNA virus that rapidly mutates, except for some...

In Ecuador, more than 50% of the milk produced was informally marketed, consequently, the mean of this study was to assess the quality of this milk specifically within the province of Pichincha, the largest milk producer. A total of 650 samples were gathered from the eight cantons within the province. The parameters that exhibited the highest level...

Background and Aim The diagnosis of bovine brucellosis in animals vaccinated with strain-19 (S19) and Rose Bengal (RB)-51 strain vaccines can be misinterpreted due to false positives. This study aimed to compare diagnostic tests for detecting bovine brucellosis in animals vaccinated with S19 and RB51 vaccine strains. Materials and Methods Two grou...

Simple Summary Viral diseases cause high economic losses in poultry. One of them is IBH (inclusion body hepatitis) and HHS (hepatitis-hydropericardium syndrome) associated with fowl adenoviruses (FAdVs), a virus that spreads rapidly by feces. Thus, the aim of the present study was to detect, quantify, and identify the genotypes of FAdVs that are ci...

Avian infectious laryngotracheitis (ILT) is a respiratory disease that causes severe economic losses in the poultry industry, mainly due to high morbidity and mortality and reduced egg production. Molecular characterization was performed on samples collected from flocks in the Brazilian States of São Paulo, Pernambuco, and Minas Gerais during 2015...

Background and Aim: Several Ecuadorian farms use human test strips (cheaper than veterinary strips) to diagnose bovine ketosis; however, their reliability is unknown. This study aimed to determine the confidence level of human strips for the detection of ketosis in bovines by comparing two diagnostic methods for ketosis: one used in bovines (gold s...

Chicken parvovirus (ChPV) is an agent frequently associated with runting stunting syndrome (RSS). This syndrome has been reported in association with ChPV in many countries, including Brazil; however, studies characterizing the virus on a molecular level are scarce, and ChPV pathogenicity in day-old chicks remains unclear. The aim of the present wo...

Simple Summary Poultry production in Brazil is a very important economic activity that provides chicken meat and eggs to global markets. Chicken astrovirus is an enteric virus related to enteric problems in chickens of several ages, but which primarily affects young chickens. Chicken astrovirus has been associated with white chick syndrome (WCS) wo...

Infectious bronchitis (IB) is one of the avian diseases with the greatest impact on poultry farming worldwide. In Brazil, strain BR-I (GI-11) is the most prevalent in poultry flocks. The present study aimed to develop a seminested RT-PCR assay specific for the diagnosis of BR-I IBV in Brazilian samples, targeting subunit 1 of the S gene. The detect...

Runting-stunting syndrome (RSS) is one of the diseases associated with many detected viruses. In Brazil, there were reports of several enteric disease outbreaks in chickens in which avian nephritis virus (ANV) was detected; however, the role of ANV in the outbreaks and whether the virus was a causative agent of these cases of enteric diseases were...

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 musc...

Many viruses have been associated with runting and stunting syndrome (RSS). These viral infections mainly affect young chickens, causing apathy, depression, ruffled feathers, cloacal pasting, and diarrhea. Chicken Parvovirus (ChPV) is such an infection and has been detected in chickens showing signs of enteric diseases worldwide. Therefore, the pre...

1. Infectious laryngotracheitis (ILT) is a respiratory disease that affects the poultry industry worldwide. It is common in flocks with high bird density, causing major economic losses. 2. In this study, a SYBR® FAST PCR double-strand DNA intercalating agent assay was performed for the detection of ILTV in clinical samples in comparison with a conv...

Enteric viruses play an important role in the Brazilian poultry industry due to the economic impact of resulting low yields of broilers, layers, and breeders. The most common enteric viruses affecting commercial flocks in Brazil include Fowl Adenovirus of group I (FAdV-I), Chicken Parvovirus (ChPV), Chicken Astrovirus (CAstV), Avian Nephritis Virus...

Avian adenovirus has been reported in many countries and is an infectious agent related with inclusion body hepatitis, hepatitis-hydropericardium syndrome (HHS), and respiratory and enteric conditions in chickens worldwide. The objective of this study was to detect and establish the molecular sequences of the hexon gene from the avian adenovirus st...

A comparative survey between non-systemic (paratyphoid Salmonellae) and systemic (S. Pullorum and S. Gallinarum) Salmonella strains was performed to produce a virulence gene profile for differentiation among the groups. The following virulence genes were evaluated: invA, spvC, sefC, pefA, fimY, sopB, sopE1, stn and avrA. There are substantial diffe...

El peróxido de hidrógeno, en leche cruda, es utilizado para enmascarar la acidez de leche contaminada con bacterias y perjudica a microorganismos beneficiosos para la elaboración de derivados. Por esta razón, en Ecuador, su uso está prohibido por la NTE INEN 9. Se determinó el tiempo de eliminación del mismo y su efecto en características físico-qu...

El peróxido de hidrógeno, en leche cruda, es utilizado para enmascarar la acidez de leche contaminada con bacterias y perjudica a microorganismos beneficiosos para la elaboración de derivados. Por esta razón, en Ecuador, su uso está prohibido por la NTE INEN 9. Se determinó el tiempo de eliminación del mismo y su efecto en características físico-qu...

• Infectious bronchitis virus (IBV) variants in Brazil were isolated during 2010-2015 for epidemiological and molecular analysis to characterise the different variants and perform a bioinformatic analysis to compare with sequences of variants collected over the previous 40 years. • Of the 453 samples examined, 61.4% were positive for IBV and 75.9%...

Milk is one of the products that can be adulterated in many ways affecting the quality of this and its derivatives. Glucomacropeptide (GMP) is a protein that is found only in the whey from the production of fresh cheese, enzymatically obtained from the coagulation of casein and which is commonly used to adulterate fresh or powdered milk. The aim of...

Digestive strategies are considered a key factor for healthy growth and conservation of the Galapagos symbol animal. In the breeding center of Isabela Island there is no nutrition studies on giant tortoise bred in captivity, which are exclusively fed with otoy, yautia or malanga (Xanthosoma sagitifolium). In the present study we worked with 60 juve...

Milk production in Ecuador has enormous economic importance and large-, medium-and small-scale producers all participate in the market. There are multiple climatic regions, and dairy production is present in every one of them. High ambient temperatures in the Ecuadorian tropics represent a key challenge to the conservation of milk in the custody of...

Resumen La investigación se realizó para determinar el tiempo de eliminación del peróxido de hidrógeno (H 2 O 2) y su efecto en las características físico-químicas y microbiológicas en leche cruda. En el Ecuador, el uso de este conservante químico es prohibido por la NTE INEN 9. Se tomaron 12 muestras diarias: 6 con conservante (Bronopol) y 6 sin c...

Enteric disease is a multifactorial problem in chickens, which causes gastrointestinal alterations, elevated feed conversions and impairment. In the last years, several enteric viruses were implicated in enteric disease; case reports have shown their presence alone or in concomitant infections during outbreaks and have suggested that they might be...

Chicken astrovirus (CAstV) is one of many viruses related to enteric diseases in poultry that are associated with Runting-Stunting Syndrome (RSS), which affects young chickens. CAstV was also recently associated with an unusual condition in chicks called “white chicks.” Some hatcheries in certain states of Brazil have reported several incubation pr...

Enteric disorders are an important cause of economic losses in broiler chickens worldwide. Several agents have been associated with enteric problems, such as viruses, bacteria, and parasites. In this study, broiler chickens showing signs of enteric disorders were subjected to molecular diagnosis for several viral agents and also for pathological ex...

Infectious laryngotracheitis (ILT) is a respiratory disease of great importance that causes serious economic losses in the poultry industry. Its control is based on biosecurity procedures and vaccination programs that use live attenuated vaccines such as tissue culture origin (TCO), chicken embryo origin (CEO), and vectored vaccines. However, probl...

As doenças entéricas que acometem as aves de produção são consideradas multifatoriais. Comumente, são denominadas de síndrome de refugagem ou como " runting-stunting syndrome (RSS) ". Esta síndrome provoca alterações gastrointestinais, aumento da conversão alimentar e diminuição de ganho de peso (Moura-Alvarez et al., 2014). Entre os agentes relaci...

Infectious laryngotracheitis (ILT) is a highly infectious respiratory disease that causes morbidity and mortality in commercial chickens. Despite the use of attenuated vaccines, ILT outbreaks have been described in broiler and long-lived birds. Molecular approaches, including polymerase chain reaction-restriction fragment length polymorphism (PCR-R...

Astroviruses have been associated with enteric disorders in many animal species, including chickens. Here, we describe the isolation, propagation, and pathological characteristics of chicken astrovirus (CAstV) in specific pathogen free (SPF) chicken embryonated eggs (CEE) from chickens with diarrhea and runting-stunting syndrome. The CEE were inocu...

Abstract 1. The presence of parvovirus in chickens with enteric disease was investigated in commercial flocks in Brazil. 2. The intestinal contents of chickens exhibiting clinical signs of diarrhoea, weight loss or mortality were examined, and chicken parvovirus (chPV) was identified using a PCR assay. The samples were sequenced and inoculated into...

A bronquite infecciosa das galinhas (BIG) é uma doença viral altamente contagiosa que causa grandes perdas à indústria avícola. O agente infeccioso é um Gammacoronavirus da espécie dos coronavírus aviários (Infectious Bronchitis Virus – IBV) que possui uma alta taxa de mutação gerando variantes virais com uma frequência maior que outros patógenos,...

Commercial broiler flocks from a farm located in the State of São Paulo, Brazil, presented diarrhea, depression, increased mortality and poor weight gain. Upon post-mortem examination, classical signs of Inclusion Body Hepatitis/Hydropericardium Syndrome (IBH/HPS) were observed, including enlarged pale yellow-colored livers and straw-colored liquid...

Enteric disease is a worldwide multifactorial problem in chickens that causes gastrointestinal alterations along with elevated feed conversions, poorly digested feed, decreased weight gain, poor feathering and high mortality. Recently, enteric viruses have been gaining notoriety due to increasing reports suggesting that they might play a determinan...

Twenty-two flocks of turkeys affected by enteric problems, with ages between 10 and 104 days and located in the Southern region of Brazil, were surveyed for turkey by PCR for turkey astrovirus type 2 (TAstV-2), turkey coronavirus (TCoV), hemorrhagic enteritis virus (HEV), rotavirus, reovirus, Salmonella spp., and Lawsonia intracellularis (Li) infec...

Several viruses have been identified in recent years in the intestinal contents of chickens and turkeys with enteric problems, which have been observed in commercial farms worldwide, including Brazil. Molecular detection of these viruses in Brazil can transform to a big threat for poultry production due to risk for intestinal integrity. This diseas...

Poultry enteric diseases are an important economic problem involving many etiologic agents, including enteric viruses. Several viral agents have been detected around the world in enteric contents isolated from commercial chicken and turkeys flocks that initially appear healthy but exhibit enteric signs, such as diarrhoea, decreased food consumption...

Poult enteritis complex has been associated with enteritis and reduction in growth rates in commercial turkeys worldwide. Intestinal samples from 76 turkey flocks from different Brazilian states affected or not with intestinal disorders were evaluated for the presence of adenovirus groups 1 and 2 (TAV), astrovirus types 1 and 2 (TAstV-1 and TAstV-2...