Fatal Africanized bee attack in captive non-human primates (Saimiri ustus and Sapajus libidinosus).

Bee stings (BS) are a life-threatening issue and a growing concern for public health and animals in the Americas. We describe the clinical, pathological, and ultrastructural findings of a massive lethal bee attack in two non-human primates (NHPs). Both animals showed BS scattered throughout the skin, surrounded by a local reaction, diffuse pulmonary congestion, edema, hemorrhage, and remarkable degeneration and necrosis of renal epithelial cells from the proximal and distal tubules, characterizing a systemic bee envenomation reaction.

Utero-Cutaneous Fistula in Ruminants: Characterization of the First Cases in Ewes and Cows.

Reports on UCF in animals are still lacking in veterinary literature. Detailed clinical signs, laboratory findings, and follow-up information from the first cases of UCF in two ewes and two cows are provided. The cases occurred over a 12-year period. All ruminants presented a fistulous tract or perforated wound on the right ventral abdomen, emitting a foul-smelling secretion possibly associated with macerated fetal parts or placental remains. Laboratory findings included anemia, leukocytosis by neutrophilia, and hyperfibrinogenemia in one ewe, and hyperfibrinogenemia in one cow. Ovariohysterectomy and fistulectomy were performed in one ewe, while the other three ruminants were submitted for the removal of fetal parts and placental remains through the UCF. Two ewes died within 12-48 h, and the two Nelore cows had an uneventful recovery, achieving secondary intention healing within 30 to 35 days. As a never-reported or unnoticed disease of the reproductive tract, UCF is an unusual consequence of dead fetus retention in an end-stage pregnancy and a potentially life-threatening condition in ruminants, especially ewes. Further broad studies in large herds of cattle and small ruminant flocks must be conducted to estimate the incidence of UCF and ensure improvements in the diagnosis and knowledge of pathogenesis, aiming at prevention.

Therapeutic Effects of Zymomonas mobilis on Experimental DSS-Induced Colitis Mouse Model.

Zymomonas mobilis, a Gram-negative bacteria observed in some popular beverages, is considered safe and has been studied for its potential therapeutic benefits. In this study, we explored its effects on the inflammatory process, tissue integrity, differential gene expression, and microbiota composition in an experimental dextran sulfate sodium (DSS)-induced colitis model in mice. As a result, Z. mobilis alleviated the symptoms caused by DSS administration, as indicated by reduced weight loss, disease activity index, a significant reduction in the colon weight/length ratio, and histopathological improvement. Also, Z. mobilis could restore the mucosal barrier as well as increase the expression of Muc3 and Ocln genes. An analysis of 16S rRNA sequences showed that Z. mobilis alters gut microbiota, increasing Akkermansia muciniphila abundance and decreasing Escherichia coli. Furthermore, Z. mobilis seems to be involved in potentiating a regulatory phenotype by inducing immunomodulatory genes like Tgfb, Il5, Il10, and Foxp3 and reducing the relative mRNA expression of proinflammatory cytokines TNF, Il6, and Il17. Our data suggest that Z. mobilis could alleviate disease progression and be considered a possible probiotic adjuvant for pathologies of the bowel.

Sanitizing Hatching Eggs with Essential Oils: Avian and Microbiological Safety.

Increased meat and egg production leads to concomitant changes in poultry practices, including the indiscriminate use of formaldehyde to sanitize hatching eggs. Although this sanitizer aids in the increase in poultry production, its toxic potential for man and for avian embryos represents an obstacle to its long-term use. This review assesses whether essential oils fit into the context of hatching egg contamination, reviewing their antimicrobial efficiency, toxicity to poultry embryos and chicks, and their sanitizing effects on poultry production parameters. Studies have indicated that, because they are safer, most of the essential oils studied can be a potential substitute for formaldehyde for minimizing microbial exposure of hatching eggs and embryos. However, complementary studies on the microbiological profile of embryos and chicks hatched from eggs sanitized with essential oils need to be carried out and the economic feasibility of the candidate products should also be considered.

Cervical Vertebral Stenotic Myelopathy in a Nelore Calf.

This paper aims to report clinical, laboratory, radiographic, and pathological features in a case of cervical vertebral stenotic myelopathy (CVSM) affecting a 4-month-old Nelore calf for the first time. During physical examination, the calf could stand if assisted when lifting by the tail but fallen to the ground when trying to walk. Attempts to flex and extend the neck to the right side failed. Radiographs findings consisted of reduced intervertebral spaces, and misalignments between the endplates, more evident between the C3 and C4 vertebrae, resulting in narrowing of the spinal canal and compression of the spinal cord. Grossly, C4 showed cranial articular surface malformation, abnormal metaphyseal growth plate development, reduced vertebral body size and deformity. Histologically, C4 showed an abnormal vertebral bone development characterized by moderate replacement of trabecular bone by fibrous tissues, multifocal areas of dystrophic hyaline cartilage development, and cartilaginous growth failure along the metaphyseal growth plate. Cervical spinal cord within the stenotic vertebral canal showed swollen neurons with central chromatolysis, areas of Wallerian degeneration, and necrotic debris. In contrast with the well-known Wobbler syndrome in horses, the etiology of CVSM in cattle remains undetermined, and further genetic and pathological studies must be conducted to elucidate it.

Pancreatic eurytrematosis in small ruminants: A forgotten disease or an untold history?

Trematodiosis are among the most neglected parasitic diseases worldwide. The pancreatic eurytrematosis (PE) is a chronic parasitic infection mostly reported in cattle but has been unnoticed in small ruminants for many decades. Our review showed PE has been recorded as scattered regional reports in goats and sheep, mainly in Asia and Eastern Europe. Eurytrema coelomaticum, Eurytrema cladorchis, and Eurytrema pancreaticum have been the main pathogenic species infecting pancreatic ducts of small ruminants. Climatic, environmental, and regional conditions in both hemispheres may support the survival and feasibility of intermediate hosts and parasitic forms, enabling the emergence and spread of PE in small ruminants. As a primarily asymptomatic condition, PE in goats and sheep flocks may also have a high prevalence, causing severe parasitic pancreatitis, production losses, and death. There is little information on anthelmintic therapeutics for PE in small ruminants, and most used anti-fluke drugs are ineffective. PE is likely more unnoticed than a neglected trematodiosis in goats and sheep, or both from a global perspective.

Immunophenotypical and pathological changes in dogs experimentally infected with Ehrlichia canis.

Canine monocytic ehrlichiosis (CME) is one of the most important tick-borne diseases worldwide, with multisystemic presentations. Immune dysregulation has been proposed as the primary mechanism involved in its pathogenesis and in tissue injury in dogs with CME. Experimental infection of German Shepherd dogs in the present study demonstrated that CME caused marked pathological changes in their lymph nodes and spleen, and also gave rise to mononuclear infiltration in organs and tissues. Immunophenotyping of cells in lymph nodes, spleen and injured tissues highlighted differences in lymphocyte subsets, local expression of immunoglobulin subclasses and MHCII molecules between infected and control dogs. These findings suggest that the immunophenotypic and immunopathological changes in dogs with acute experimental CME are related to Th1 bias and compartmentalized immune response.

Downer cow syndrome causing rhabdomyolysis and acute renal failure in a 17-month-old Guzerá heifer / Síndrome da vaca caída causando rabdomiólise e insuficiência renal aguda em uma novilha Guzerá de 17 meses

The downer cow syndrome (DCS) is characterized by an alert cow showing inability or reluctance to stand for 12 hours or more. This paper reported clinical, laboratory, and pathological findings in a Guzerá heifer with rhabdomyolysis, pigmenturia and acute renal failure following DCS. A 17-month-old Guzerá heifer was transported via a 350-km ride in a truck and showed sternal recumbency and severe difficulty in standing and walking. Neurological examination was unremarkable, and the heifer presented normal response to cranial nerves and spinal cord tests. Rectal palpation revealed a 5-month gravid uterus. No other abnormalities were noted in the pelvis or around the coxofemoral joints. Biochemical abnormalities included extremely high muscular enzyme activities (creatine phosphokinase and aspartate aminotransferase) and high creatinine levels. Urinalysis revealed blackish and cloudy urine, proteinuria, and a positive occult blood test. Spinal cord ultrasonography showed no abnormalities. This report highlighted an uncommon clinical presentation (myoglobinuria) and pathological findings in a heifer with DCS as a consequence of severe compressive muscle damage. Practitioners and producers must be aware of the risk of careless road transportation for long distances of cattle, especially obese cows, avoiding unnecessary suffering and expenses due to DCS.

A síndrome da vaca caída (SVC) é caracterizada por um bovino alerta que mostra incapacidade ou relutância em permanecer em estação por 12 horas ou mais. O objetivo deste trabalho é relatar os achados clínicos, laboratoriais e patológicos em uma novilha Guzerá com rabdomiólise, pigmentúria e insuficiência renal aguda após a SVC. Uma novilha da raça Guzerá, de 17 meses de idade, foi transportada de caminhão por 350 km e apresentou decúbito esternal, grande dificuldade para assumir estação e caminhar. O exame neurológico não demonstrou alterações, e a novilha possuía resposta normal aos testes de nervos cranianos e medula espinhal. A palpação retal revelou útero grávido de cinco meses. Nenhuma outra anormalidade foi observada na pelve ou na região das articulações coxofemorais. As anormalidades bioquímicas incluíram atividades de enzimas musculares (creatina fosfoquinase e aspartato aminotransferase) extremamente aumentadas e níveis elevados de creatinina. A urinálise revelou urina enegrecida e turva, proteinúria e teste de sangue oculto positivo. O exame ultrassonográfico da medula espinhal não apresentou anormalidades. Este relato evidencia uma apresentação clínica (mioglobinúria) e achados patológicos incomuns em uma novilha com SVC em consequência de extensa lesão muscular compressiva. Veterinários e produtores devem estar atentos aos riscos do transporte rodoviário descuidado por longas distâncias de bovinos, especialmente vacas obesas, evitando assim sofrimento e despesas desnecessárias decorrentes da SVC.

Capybara (Hydrochoerus hydrochaeris) exposure to Rickettsia in the Federal District of Brazil, a non-endemic area for Brazilian spotted fever.

In this study, whole blood samples and ticks were collected from 57 capybaras in recreational areas in the Federal District, Brazil, aiming to investigate the presence of Rickettsia spp. using polymerase chain reaction (PCR) and indirect immunofluorescence (IFAT) assays. None of the capybara blood samples yielded rickettsial DNA by PCR. Among 55 capybara serum samples tested by IFAT, 53 (96.3%) reacted to Rickettsia spp. Among these, 21 (39.6%) identified the R. bellii antigen as the probable antigen involved in a homologous reaction (PAIHR), whereas 2 (3.8%) identified the R. parkeri antigen. Ticks collected from capybaras were identified as 173 Amblyomma sculptum and 410 A. dubitatum, in addition to nine Amblyomma spp. larvae. A sample of 231 ticks was subjected to DNA extraction and PCR for Rickettsia species. None of 122 A. sculptum yielded rickettsial DNA. Molecular evidence of R. bellii was found in 25/108 (23.1%) and of Rickettsia sp. strain Cooperi (R. parkeri-like agent) in 2/108 (1.9%) of the A. dubitatum samples. These results suggest a greater exposure to R. bellii in these capybara populations, in addition to a more significant number of A. dubitatum, which might characterize the Federal District region as not endemic for Brazilian spotted fever.

Eurytrema coelomaticum natural infection in small ruminants: a neglected condition.

Pancreatic eurytrematosis (PE) is an under diagnosed and neglected parasitosis in goats and sheep in the Americas. Clinical and pathological features of PE are not well defined in small ruminants worldwide. Natural cases of PE in small ruminants were detected in the Federal District, Brazil. A survey of necropsy records, including epidemiological and clinicopathological data, in goats and sheep was conducted. Most cases of PE occurred during the rainy season in adult females, with an incidence of 12.9% in goats and 0.8% in sheep. Clinical signs varied from asymptomatic infections to anorexia, lethargy, weakness, marked weight loss and death in some goats. Overall, most cases of PE in goats and sheep were incidental necropsy findings with minor pancreatic lesions. Three goats, however, showed severe chronic pancreatitis, dilation of major pancreatic ducts with numerous trematodes present and marked abdominal fat necrosis. Morphological and molecular characterization of flukes detected Eurytrema coelomaticum. Our findings shed light on the prevalence of E. coelomaticum infections in small ruminants in the region and highlight the possibility of severe and lethal cases in goats. PE must be further investigated in small ruminant populations in relevant livestock production regions of the Americas.

Squamous cell carcinoma of the footpad with systemic metastasis in a captive crowned solitary eagle (Buteogallus coronatus).

Squamous cell carcinomas (SCC) are one of the most common tumors of the tegument that can have a misdiagnosis of chronic skin wounds. An adult captive crowned solitary eagle presented an indolent wound-like ulcer on the footpad and a fatal outcome. An infiltrating tumoral mass in the foot and multiple tumoral metastatic nodules in visceral organs were detected. The neoplasm was composed of atypical squamous cells with strong positivity for cytokeratin, "keratin pearl" structures, and marked invasion of tissues confirming a diagnosis of metastatic SCC. This might be the first report of an SSC with metastasis on the footpad in a captive Chaco eagle, which is one of the endangered species of birds of prey.

Nasal Melanophoroma in a Captive Green Iguana (Iguana Iguana).

Green iguanas are arboreal lizards, common as pet animals and in captivity. Knowledge of neoplasms in iguanas is scarce, and a challenge to their prevention, treatment, and prognosis. A captive green iguana showed a pigmented nasal exophytic neoplasm. Tumor cells were spindle-shaped to epithelioid with a variable amount of dark-brown or black granular melanin within the cytoplasm, and also presented cytoplasmic positivity for Melan-A and S100. Transmission electron microscopy evidenced intracytoplasmic melanosomes and premelanosomes and provided a definitive diagnosis of a nasal melanophoroma. Full characterization of the clinicopathological and ultrastructural features of the melanophoroma may contribute to the limited knowledge concerning cutaneous neoplasms in green iguanas.

Arytenoid chondritis in two calves / Condrite aritenóide em duas bezerras

ABSTRACT: Although, calf diphtheria and necrotic laryngitis are common infections in the oral cavity's soft tissues, arytenoid chondritis is addressed as a serious but rarely diagnosed complication in cattle. This paper aimed to describe clinical, laboratory, imaging, and pathological findings in two calves with arytenoid chondritis. A 2-month-old Jersey calf and a 3-month-old Girolando calf presented 40-days history of respiratory distress. In the former, oral endoscopy revealed enlarged and immobile arytenoids with major involvement of the left arytenoid, causing severe distortion and partial obstruction of the rima glottidis. In the latter, latero-lateral radiography of the head revealed radiolucent areas and thickening at the level of the larynx to the dorsal trachea. Pathological examination of one calf showed neutrophilic multifocal inflammatory infiltrate and areas of necrosis in the cricoarytenoid cartilage, surrounded by abscessation. Definitive diagnosis of arytenoid chondritis in these two calves was established on the basis of clinical, laboratory, imaging (endoscopy and radiography), and pathological findings. Daily and careful observation of the herds and the use of ancillary diagnostic methods allowed the early diagnosis of the disease, and accurate diagnosis can improve prognosis and increase treatment success rate.

RESUMO: Embora a difteria em bezerros e a laringite necrótica sejam infecções comuns nos tecidos moles da cavidade oral, a condrite aritenoide é considerada uma complicação grave, mas raramente diagnosticada em bovinos. Este trabalho tem como objetivo descrever os achados clínicos, laboratoriais, de imagem e patológicos em duas bezerras apresentando condrite aritenoide. Uma bezerra Jersey de dois meses de idade e uma bezerra Girolando de três meses de idade apresentavam dificuldades respiratórias por 40 dias. Na primeira, a endoscopia oral revelou aritenoides aumentadas e imóveis, com grande envolvimento da aritenoide esquerda, causando distorção grave e obstrução parcial de rima glottidis. Na segunda, a radiografia látero-lateral da cabeça revelou áreas radioluscentes e espessamento ao nível da laringe até a traqueia dorsal. O exame patológico de uma bezerra revelou infiltrado inflamatório multifocal neutrofílico e áreas de necrose na cartilagem cricoaritenóide, circundadas por abscessos. O diagnóstico definitivo de condrite aritenoide nessas duas bezerras foi estabelecido com base nos achados clínicos, laboratoriais, de imagem (endoscopia e radiografia) e patológicos. O monitoramento diário e minucioso dos rebanhos e o uso de métodos auxiliares de diagnóstico permitem o diagnóstico precoce da enfermidade, sendo que o diagnóstico preciso pode melhorar o prognóstico e aumentar a taxa de sucesso do tratamento.

Socio-epidemiological characterization of human leptospirosis in the Federal District, Brazil, 2011-2015.

INTRODUCTION: Human leptospirosis (HL) in the Federal District (DF), Brazil, is endemic and requires studies to characterize the socio-epidemiological profile of the vulnerable population. METHODS: Seventy-nine autochthonous cases of HL between 2011-2015 were analyzed based on the databases of the Epidemiological and Environmental Health Surveillance Department, DF. RESULTS: The male population aged 31-45 years represented 86% of the leptospirosis cases; most belonged to the social classes D and E. CONCLUSIONS: In the DF, preventive measures should be concentrated on economically active male adults of social classes C, D, and E with the aim of promoting health.

Socio-epidemiological characterization of human leptospirosis in the Federal District, Brazil, 2011-2015

Abstract INTRODUCTION: Human leptospirosis (HL) in the Federal District (DF), Brazil, is endemic and requires studies to characterize the socio-epidemiological profile of the vulnerable population. METHODS: Seventy-nine autochthonous cases of HL between 2011-2015 were analyzed based on the databases of the Epidemiological and Environmental Health Surveillance Department, DF. RESULTS: The male population aged 31-45 years represented 86% of the leptospirosis cases; most belonged to the social classes D and E. CONCLUSIONS: In the DF, preventive measures should be concentrated on economically active male adults of social classes C, D, and E with the aim of promoting health.

Experimental Neospora caninum infection in chickens (Gallus gallus domesticus) with oocysts and tachyzoites of two recent isolates reveals resistance to infection.

The importance of birds in the biological cycle of Neospora caninum is not clear. We report unsuccessful Neospora infection in chickens (Gallus gallus domesticus) using two isolates of N. caninum. In experiment #1, 30 White Leghorn chickens were orally inoculated with viable N. caninum oocysts (NC-SP1 isolate, 200 oocysts per bird) via the crop at 21days of age. Groups of three birds were euthanised at intervals of 7days (a total of 9weeks) and one group was challenged with the same oocyst dose at 37daysp.i. and observed for 11weeks. Blood samples were collected weekly, and sera were tested using IFAT. Chicken tissues were collected for PCR, quantitative PCR and immunohistochemistry. Two dogs approximately 45days of age were fed with tissues from chickens euthanised at 138 and 159daysp.i. The results indicated that the chickens were resistant to neosporosis as revealed by failure to seroconvert, to detect parasite DNA or N. caninum antigen by immunohistochemistry in inoculated bird tissues, and by no oocyst excretion by the dogs fed avian tissues. Similar results were obtained in experiment #2, in which 34 1-week-old chickens were each s.c. inoculated with 100,000 tachyzoites of the NcWTDMn1 isolate of N. caninum. The chickens were euthanised on days 7, 15, 22, 28, 36 and 60p.i. At necropsy, all tissues and serum from each bird were collected. All chickens remained asymptomatic, and N. caninum antigen was not detected by immunohistochemistry. Seven chickens euthanised at day 60p.i. demonstrated low (1:25 dilution) levels of antibodies by using the Neospora agglutination test. Two 12-week-old dogs fed tissues pooled from 10 inoculated chickens euthanised at day 60p.i. did not excrete N. caninum oocysts. This investigation indicates that chickens are resistant to experimental infection by N. caninum.

Human leptospirosis in the Federal District, Brazil, 2011-2015: eco-epidemiological characterization

Abstract INTRODUCTION: Leptospirosis is an infectious disease that affects more than 5,000 people per year in Brazil. The Federal District (FD) lacks epidemiological studies of human leptospirosis and presents concerning rates of this disease, especially considering its lethality. METHODS: Seventy-nine autochthonous human cases of leptospirosis between 2011 and 2015 were analyzed, with the probable infection location serving as a basis for the collection and analysis of the environmental and epidemiological variables. RESULTS: The incidence of the disease ranged from 0.68-13.39 per 100,000 inhabitants in 21 of the 31 administrative regions that compose the FD. The local profile of human leptospirosis was predominantly associated with urban areas during the rainy season, population access to the sewage network, the treated water network, and the public garbage collection service. The vast majority of cases had a strong association with synanthropic rodents at the infection sites. CONCLUSIONS: In order to prevent and control potentially lethal human leptospirosis infection, the eco-epidemiological characterization of this disease is a valuable tool for public policies of prevention, control, and surveillance. In addition to population awareness, the systematized control of synanthropic rodents could be the main health action to reduce the incidence of this disease in the FD.

Human leptospirosis in the Federal District, Brazil, 2011-2015: eco-epidemiological characterization.

INTRODUCTION: Leptospirosis is an infectious disease that affects more than 5,000 people per year in Brazil. The Federal District (FD) lacks epidemiological studies of human leptospirosis and presents concerning rates of this disease, especially considering its lethality. METHODS: Seventy-nine autochthonous human cases of leptospirosis between 2011 and 2015 were analyzed, with the probable infection location serving as a basis for the collection and analysis of the environmental and epidemiological variables. RESULTS: The incidence of the disease ranged from 0.68-13.39 per 100,000 inhabitants in 21 of the 31 administrative regions that compose the FD. The local profile of human leptospirosis was predominantly associated with urban areas during the rainy season, population access to the sewage network, the treated water network, and the public garbage collection service. The vast majority of cases had a strong association with synanthropic rodents at the infection sites. CONCLUSIONS: In order to prevent and control potentially lethal human leptospirosis infection, the eco-epidemiological characterization of this disease is a valuable tool for public policies of prevention, control, and surveillance. In addition to population awareness, the systematized control of synanthropic rodents could be the main health action to reduce the incidence of this disease in the FD.

Intestinal obstruction caused by neoplasms in two cows / Obstrução intestinal causada por neoplasias em duas vacas

ABSTRACT: In cattle, abdominal tumors leading to partial or total intestinal obstruction are rare. Here, it is described the clinico-pathological findings of two cows with intestinal obstruction by neoplasms. A crossbred cow presented apathy, weight loss, constipation, enophthalmos, ruminal and intestinal hypomotility, and abdominal distension in the right ventral quadrant. Pathological examination revealed bilateral ovarian teratoma. The other case was a cow that in the past 2 years had several episodes of squamous cell carcinoma in the third eyelid and vulva. During the 6 days prior to investigation, clinical signs of constipation and tenesmus were noted. Nodular and friable masses were located in the vulva, right third eyelid and cranially to the right kidney that were identified as poorly differentiated metastatic carcinoma of the adrenal cortex. To our knowledge, these are probably the first reports of ovarian teratoma and adrenal carcinoma causing clinical signs of intestinal obstruction in cattle.

RESUMO: Em bovinos, tumores abdominais que levam à obstrução intestinal parcial ou total são raros. Neste relato, descrevemos os achados clínico-patológicos de duas vacas com obstrução intestinal por neoplasias. Uma vaca mestiça apresentava apatia, perda de peso, constipação, enoftalmia, hipomotilidade ruminal e intestinal e distensão abdominal no quadrante ventral direito. O exame patológico revelou teratoma ovariano bilateral. O outro caso foi uma vaca que, nos últimos 2 anos, teve episódios de carcinoma de células escamosas na terceira pálpebra e vulva. Durante 6 dias antes da investigação, foram observados constipação e tenesmo. Massas nodulares e friáveis foram localizados na vulva, terceira pálpebra direita e cranial ao rim direito, que foram identificadas como carcinoma metastático pouco diferenciado do córtex adrenal. Ao nosso conhecimento, estes são os primeiros relatos de teratoma ovariano e carcinoma adrenal causando sinais clínicos de obstrução intestinal em bovinos.

Frequency of histopathological changes in Howler monkeys ( Alouatta sp.) naturally infected with yellow fever virus in Brazil.

INTRODUCTION: Due to the importance that Howler monkeys have on the yellow fever (YF) epidemiological sylvatic cycle in Brazil, more accurate morphological diagnostic criteria needs to be established, especially considering the differences that may exist between the genera of Brazilian non-human primates (NHPs) involved in yellow fever virus (YFV) epizootics. METHODS: Records of YF epizootics in NHPs in Brazil between 2007 and 2009 were obtained from the Brazilian Ministry of Health database to select YF positive (n=98) Howler monkeys (Alouatta sp.) for this study. The changes described in the histopathological reports were categorized by organ and their frequencies calculated. RESULTS: The most frequent lesions observed in the animals with YF were hepatocyte apoptosis (Councilman body formation), midzonal hepatocyte necrosis, steatosis, liver hemorrhage, inflammatory mononuclear cell infiltration of the liver, renal acute tubular necrosis and interstitial nephritis. Midzonal hepatocyte necrosis, steatosis and hemorrhage presented positive correlations with apoptosis of hepatocytes, suggesting strong YFV pathogenic effect association; they were also the main histopathological changes in the Alouatta sp. A pronounced negative correlation between apoptosis of hepatocytes and hepatic mononuclear cell infiltration pointed to significant histopathological differences between YFV infection in Howler monkeys and humans. CONCLUSIONS: The results warn that NHPs may exhibit different response patterns following YFV infection and require a more careful diagnosis. Presumptive diagnosis based on primate histopathological lesions may contribute to public health service control.