The clinical, pathological and microbiological outcome of an Escherichia coli O2:K1 infection in avian pneumovirus infected turkeys

The purpose of this study was to evaluate the effect of an Escherichia coli infection in avian pneumovirus (APV)-infected turkeys. One group of 2-week-old specific pathogen-free (SPF) and two groups of 3-week-old conventional (CON) turkeys were inoculated oculonasally with virulent APV subtype A alone, with E. coli O2:K1 alone or with both agents at varying intervals (1, 3, 5 or 7 days) between the two inoculations. The birds were followed clinically and examined for macroscopic lesions at necropsy. Titres of APV were determined in the turbinates, trachea, lungs and air sacs. The number of E. coli O2:K1were assessed in the turbinates, trachea, lungs, air sacs, liver and heart. In both SPF and CON turkeys, dual infection resulted in an increased morbidity and a higher incidence of gross lesions compared to the groups given single infections, especially with a time interval between APV and E. coli inoculations of 3 and 5 days. APV was isolated from the respiratory tract of all APV-infected groups between 3 and 7 days post inoculation. E. coli O2:K1 was isolated only from turkeys that received a dual infection. It was recovered from the turbinates, trachea, lungs, heart and liver. These results show that APV may act as a primary agent predisposing to E. coli colonization and invasion.     

Toxocara cati larvae persist and retain high infectivity in muscles of experimentally infected chickens

The distribution of Toxocara cati larvae in the organs of chickens (n=31), experimentally inoculated with 3000 embryonated eggs, was examined 1, 2, 3, 7, 29, 86 and 175-176 days post-infection (dpi), and the infectivity of recovered larvae was evaluated by bioassay in mice. The duodenum, liver, lungs, heart, brain, pectoral muscles (white meat), and hindlimb muscles (red meat) of the chickens were HCl-pepsin digested for larval recovery. Larvae were recovered from all chickens [mean=220.4 ± 114.9 (SD)], and although no decrease of total larval recovery was observed over time, predilection sites changed: liver (92.6% of larval recovery) at 1 dpi; lungs (77.3%) and liver (20.9%) at 2 dpi; lungs (80.8%), muscles (9.4%), and liver (8.5%) at 3 dpi; muscles (52.0%) and lungs (45.6%) at 7 dpi, whereafter most larvae were recovered from muscles: 29 dpi (99.5%), 86 dpi (99.3%) and 175-176 dpi (99.6%). In the bioassay, 52.9% of larvae from 175 to 176 days old infections in chickens established in mice, which demonstrates that T. cati larvae retain infective in the muscles of chickens for half a year. These results highlight the zoonotic potential of poultry meat as a causative agent of human toxocarosis.     

Echinococcosis/hydatidosis in western Iran

In the present study, 115 stray dogs (56 males and 59 females, mixed breed), 86 golden jackal (Canis aureus, 42 males and 44 females), 60 red foxes (Vulpes vulpes, 33 males and 27 females), and three female wolves (Canis lupus) were examined for Echinococcus granulosus infection, as well as, 32,898 sheep, 10,691 goats, 15,779 cattle and 659 buffaloes for hydatid infection from five provinces in western Iran during 3 years (1997-2000). Meanwhile fertility rates of different types and forms of cysts isolated from infected animals and the viability of protoscolices were also determined. Results indicated that 19.1% of the dogs, 2.3% of the golden jackals and 5% of the red foxes were infected with Echinococcus granulosus. 11.1% of the sheep, 6.3% of the goats, 16.4% of the cattle and 12.4% of the buffaloes were also found to be infected with hydatid cyst. The cysts isolated from liver and lungs of the sheep show higher fertility rate than the cysts of liver and lungs of goats, cattle and buffaloes.     

Efficacy of enrofloxacin, florfenicol and amoxicillin against Ornithobacterium rhinotracheale and Escherichia coli O2:K1 dual infection in turkeys following APV priming

Experimental groups of 15 susceptible 3-week-old turkeys were inoculated oculonasally with avian metapneumovirus (APV) subtype A and susceptible Escherichia coli O2:K1 and Ornithobacterium rhinotracheale (ORT) bacteria, with a 3 days interval between viral and bacterial inoculation and approximately 8h between the two bacterial inoculations. The aims of the present study were to assess the efficacy of drinking-water administration of enrofloxacin for 3 and 5 days, amoxicillin for 5 days and florfenicol for 5 days for the treatment of the resulting respiratory disease, based on clinical and bacteriological examinations. Antimicrobial treatment started 1 day after dual bacterial inoculation. After infection, the birds were examined and scored for clinical signs daily, weighed at different times, and their tracheae swabbed daily. Five birds were euthanised and examined for macroscopic lesions at necropsy at 5 days post-bacterial inoculation (dpbi) and the remainder at 15dpbi. Samples of the turbinates, trachea, lungs, sinuses, air sacs, heart, pericardium and liver were collected for bacteriological examination. Recovery from respiratory disease caused by an APV/E. coli/ORT triple infection in 3-week-old turkey poults was overall most successful after enrofloxacin treatment, irrespective of treatment duration, followed by florfenicol treatment. Compared with the untreated group, clinical signs as well as ORT and E. coli multiplication in the respiratory tract were significantly reduced by both enrofloxacin treatments and the florfenicol treatment, with the enrofloxacin treatments showing significantly better reductions than the florfenicol treatment. Five-day treatment with amoxicillin, compared with the untreated group, did not cause a significant reduction in any of the aforementioned parameters.     

Effects of continuous low-dose infusion of lipopolysaccharide on expression of E-selectin and intercellular adhesion molecule-1 messenger RNA and neutrophil accumulation in specific organs in dogs

OBJECTIVE: To determine the effects of continuous low-dose infusion of lipopolysaccharide (LPS) on the expression of E-selectin and intercellular adhesion molecule-1 (ICAM-1) mRNA and neutrophil accumulation in the lungs, liver, spleen, small intestine, and pancreas in dogs. ANIMALS: 11 healthy adult Beagles. PROCEDURE: Dogs received a continuous infusion of a low dose (10 microg/kg/h, i.v.) of LPS (Escherichia coli 055:B5) or saline (0.9% NaCI) solution (20 mL/kg/h, i.v.) for 8 hours. Activity levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (1L-6) and the number of WBCs in circulation were examined before and 1, 2, 4, and 8 hours after the onset of LPS infusion. Expression of E-selectin and ICAM-1 mRNA and the number of neutrophils in each tissue were examined. RESULTS: After the onset of LPS infusion, serum TNF-alpha and IL-1beta activities transiently increased. Thereafter, IL-6 activity increased, and high IL-6 activity was maintained throughout the experiment. In dogs in the LPS group, expression of E-selectin mRNA increased only in the lungs, and expression of ICAM-1 mRNA increased in the lungs and liver; the number of neutrophils in the tissue increased in the lungs and liver. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that expression of E-selectin and ICAM-1 mRNA increased during sepsis, particularly in the lungs and liver, and that this increase was associated with neutrophil accumulation. Hence, inhibiting the activation of endothelial cells in the lung and liver may decrease organ damage caused by accumulated neutrophils and help regulate multiple-organ dysfunction.     

Immunity to Toxocara vitulorum repeated infections in a rabbit model.

Eleven rabbits were infected with 10 embryonated eggs of Toxocara vitulorum per g body weight on Days 0, 35 and 72. Embryonated eggs and larvae were enumerated in feces on Days 1-3 after each infection. Two rabbits were killed and larvae were enumerated in small intestine, liver, lungs, skeletal muscles, heart, kidney, brain, eye, uterus, and mammary glands on Days 5, 15, 30, 65 and 101. Serum was obtained on Days 0, 5, 15, 30, 42, 50, 65, 78, 86 and 101 to perform enzyme-linked immunosorbent assays (ELISAs) and Western blots against an extract of embryonated eggs. Between 4 and 10% of the administered parasites, almost all embryonated eggs, were found in the feces after the first or second infection, but 32% (27% of them larvae) after the third. Yields of tissue parasites were 4.1% of the administered dose on Day 5, 2% on Day 15, and 0.8% on Day 30 of the first infection, 0.1% on Day 30 of the second infection, and 0.06% on Day 30 of the third. Larvae were found only in liver, lungs and muscle, including heart. Larva content declined steadily in liver and lungs from Day 5 to 30 of the first infection, was absent in the liver at Day 30 of the second, and in both organs at Day 30 of the third. Muscle larva content increased from Day 15 to 30 of the first infection, and persisted throughout the third infection. Production of IgM antibody was minimal, IgG and the sum of IgMGA antibodies increased slightly or moderately after the first and second infections, but dramatically after the third. Western blots revealed the first antigens (12) by Day 15 of the first infection. Their total number increased with time and number of infections, but some antigens disappeared, whereas new antigens appeared in the course of the observations. Four antigens (32,500-41,000 mol.wt.) may be related to protection. Comparison of the Western blot patterns of two rabbits showed differences in the antigens, recognizable for each rabbit.     

Biology and pathophysiology of Toxocara vitulorum infections in a rabbit model.

Ten female New Zealand rabbits were infected via stomach intubation with eggs of Toxocara vitulorum at a dosage of 10 embryonated eggs per gram of body weight on Days 0, 35 and 72. Ten or 4% of the administered parasites passed in the feces during the 3 days following the first or second infection, but 32% after the third infection. Many larvae were passed in the third infection, but not in the first or second. Tissue parasite yields were 4.1% on Day 5, 2% on Day 15, 0.8% on Day 30, 0.1% on Day 65 and 0.06% on Day 101. Five hundred and ninety-three larvae were recovered from liver, 243 from lungs and 0 from muscles on Day 5; 282 from liver, 138 from lungs and 21 from muscles on Day 15; 151 from liver, 21 from lungs and 50 from muscles on Day 30; 0 from liver, 26 from lungs and 15 from muscles on Day 65; 0 from liver, 0 from lungs and 9 from muscles on Day 101. No larvae were found in other tissues. The size of the muscle larvae at 30, 65 and 101 days indicated that the parasites did not develop beyond the infective stage and suggested that they were probably hypobiotic organisms. Erythrocytes, packed cell volume and monocytes decreased, but eosinophils and basophils increased, after each infection. Serum enzyme levels indicated that liver damage occured only after the first infection, but muscle injury occurred after each infection and was increasingly more precocious after each infection.     

Biology and pathophysiology of Toxocara vitulorum infections in a rabbit model

Ten female New Zealand rabbits were infected via stomach intubation with eggs of Toxocara vitulorum at a dosage of 10 embryonated eggs per gram of body weight on Days 0, 35 and 72. Ten or 4% of the administered parasites passed in the feces during the 3 days following the first or second infection, but 32% after the third infection. Many larvae were passed in the third infection, but not in the first or second. Tissue parasite yields were 4.1% on Day 5, 2% on Day 15, 0.8% on Day 30, 0.1% on Day 65 and 0.06% on Day 101. Five hundred and ninety-three larvae were recovered from liver, 243 from lungs and 0 from muscles on Day 5; 282 from liver, 138 from lungs and 21 from muscles on Day 15; 151 from liver, 21 from lungs and 50 from muscles on Day 30; 0 from liver, 26 from lungs and 15 from muscles on Day 65; 0 from liver, 0 from lungs and 9 from muscles on Day 101. No larvae were found in other tissues. The size of the muscle larvae at 30, 65 and 101 days indicated that the parasites did not develop beyond the infective stage and suggested that they were probably hypobiotic organisms. Erythrocytes, packed cell volume and monocytes decreased, but eosinophils and basophils increased, after each infection. Serum enzyme levels indicated that liver damage occured only after the first infection, but muscle injury occurred after each infection and was increasingly more precocious after each infection.     

Molecular characterization and prevalence of cystic echinococcosis in slaughtered water buffaloes in Turkey

The present study was carried out between March 2006 and June 2010. During the study nine abattoirs were visited and 166 water buffalo internal organs were examined in Black Sea Region of Turkey. It was found that 10.24% buffaloes were infected with cystic echinococcosis (CE). The rate of CE found as 3.77% in males and 21.66% in females, 37.93% in older and 4.38% in young animals. The degree of prevalence according to age and sex was statistically significant (p<0.05). CE was observed 29.41% only in liver, 47.06% only in lungs and 23.53% in both liver and lungs. Therefore, the lungs were the predominant sites of the CE in buffaloes. Molecular identification on nine isolates, based on mitochondrial cox1 sequencing analyses, revealed that six cysts belonged to G1 genotype (domestic sheep strain) while 3 samples showed variant genotypes of Echinococcus granulosus complex G1-G2-G3. Two of them showed a thymine in position 52, like G2 strain, but the rest of sequences were completely identical to strain G1; also one specimen showed a single nucleotide change compared to strain G1 (C122T).     

Prevalence of ovine progressive pneumonia in a sampling of cull sheep from western and midwestern United States.

Ovine progressive pneumonia was found to be prevalent in many major sheep-producing areas in the United States. The incidence was determined in a sampling of cull sheep (5 to 10 years of age) at slaughter. Diagnostic criteria were based on finding viral-specific immunoglobulins, virus, or lesions. Each method indicated a high incidence in samplings from midwestern and northwestern states and a relatively low incidence in the sampling from southwestern states. Of those sheep examined, precipitating immuno-globulin to the causal virus was seen in 1.0% to 67.5%, virus was isolated from the lungs of 0% to 46.2%, and lymphoid hyperplasia was seen in the lungs of 0% to 38.5%. The most common lesions in the lungs (from which virus was isolated) were multiple lymphoid nodules and increased fibromuscular tissue.     

The Retrospective Annual Surgical Incidence of Cystic Echinococcosis in Sivas,Turkey

Cystic echinococcosis is an important public health problem in our region. The aim of this study was to assess the surgical incidence of cystic echinococcosis in Sivas, Turkey. A retrospective follow‐up study was carried out between 1997 and 2004. The mean age of 124 men (39.2%) and 192 women was 36.4 years. The liver was the primary site of cyst development (76.6%), followed by the lungs (19.9%), the spleen (5.4%), the kidneys (3.5%) and the peritoneal cavity (3.2%). Mean annual surgical incidence was 6.4 per 100 000 inhabitants for a 7‐year period. The most common site of recurrence was the liver. Hepatic cysts were more frequently infected than pulmonary cysts (P < 0.05). In those patients with an infected cyst, the mean circulating eosinophil level was significantly lower than in those without. Rupture and infection were more common in men (P < 0.01). In conclusion, serious structural, legislative, surveillance, prevention and control measures for echinooccus should be undertaken in our region.     

Prevalence of hydatidosis among donkeys in northern Jordan

One hundred and thirty donkeys (Equus asinus), aged between 5 months and 14 years of age, from the Irbid Governorate in northern Jordan were necropsied between November 1997-May 1999. Of these animals, 16.9% had hydatid cysts in either their lungs and/or livers. No donkeys of 3 years of age or less were infected, where as 33.3% (22 of 66) aged 4 years or greater were infected. Intensity of infection increased with age in a linear fashion. The prevalence also increased with age approaching an asymptotic prevalence of 1 in the oldest animals. This implied there was minimal regulation of the parasite population by intermediate host immunity. The numbers of cysts in the donkeys were increasing at a rate of 0.48 cysts per year from 0.054 infections. The frequency distribution was highly aggregated, consistent with a negative binomial distribution indicating infection of donkeys was not random.     

Echinococcus ortleppi and E. granulosus G1, G2 and G3 genotypes in Italian bovines

To increase the knowledge on Echinococcus genotypes infesting cattle and water buffaloes (Bubalus bubalis) born and bred in Italy, the germinal layer of hydatid cysts was collected from the liver and the lungs of 80 animals slaughtered in 2007. Two mitochondrial genes (the cytochrome c oxidase subunit I and the NADH subunit I) were tested by PCR. Four genotypes were identified: G1 (sheep strain), G2 (Tasmanian sheep strain), G3 (buffalo strain), and G5 (cattle strain). Fertile cysts were detected only in the lungs of 4.5% of the total G1 lung cysts, of 9.4% of the total G3 lung cysts, and in the only G5 infected animal. This is the first report of Echinococcus ortleppi (genotype G5) in Italy.     

Disseminated mycoses in cattle. A study on nine autopsy cases.

Nine cases affected with disseminated mucormycosis (1.3% of all autopsy cases and 20.0% of systemic mycosis) were found among bovine systemic mycosis examined from 1975 to 1985. The disseminated lesions were found in the lungs (3 cattle), heart (2 cattle), liver (2 cattle), spleen (1 beef cattle), kidneys (1 cattle), central nervous system (1 cattle) and lymph node (1 cattle). Histological examination revealed granulomatous lesions, necrotic foci including infarcts, and thromboangiitis with the hyphae of a member of the Zygomycetes and neutrophil reaction. Granulomatous lesions with asteroid bodies were found in the liver. Metastatic foci were established from the primary lesions found in the alimentary organ (4 from the forestomach or abomasum and 1 from the tongue). One case resulted from uterine mucormycosis, and no primary lesion was found in the other 3 cattle. Complicated infection with respiratory aspergillosis occurred in 4 cases with alimentary mucormycosis. All of the 9 cattle had predisposing disorders. Six cattle had been manifested with prolonged debilitating conditions. Anemia was present in 4, leukopenia in 2 and lymphopenia in 1 cattle.     

Capillaria hepatica infection in wild brown rats (Rattus norvegicus) from the urban area of Milan, Italy

Forty-seven wild brown rats (Rattus norvegicus) collected from the urban area of Milan (Italy) were screened for Capillaria hepatica liver infection. The liver of each rat was grossly and histologically examined for the presence of C. hepatica adults, eggs and typical C. hepatica induced lesions. In 17 rats (36%) liver lesions consistent with C. hepatica infection were detected. Grossly, white-yellow nodules of 1-5 mm in diameter were present, either scattered on the liver surface or localized in a single lobe. Histologically, granulomatous liver lesions associated with eggs and/or worms were observed. The degree of gross liver involvement was moderate in most of the positive cases (71%). About 30 cases of C. hepatica infection in humans have been documented world-wide, most of which are reported in children from 1 to 5 years of age. Our results suggest that the potential transmission of C. hepatica to children in the study area should be considered an important health issue.     

Apoptosis in the lungs of pigs infected with porcine reproductive and respiratory syndrome virus and associations with the production of apoptogenic cytokines

Apoptosis was studied in the lungs of pigs during an infection with a European strain of porcine reproductive and respiratory syndrome virus (PRRSV) and it was examined if cytokines were involved in the induction of apoptosis. Twenty-two 4- to 5-week-old gnotobiotic pigs were inoculated intranasally with 10(6.0) TCID50 of the Lelystad virus and euthanised between 1 and 52 days post inoculation (PI). The lungs and broncho-alveolar lavage (BAL) cells were assessed both for virus replication and apoptosis; BAL fluids were examined for interleukin (IL)-1, tumour necrosis factor-alpha and IL-10. Double-labellings were conducted to determine the relation between virus replication and apoptosis and to identify the apoptotic cells. Apoptosis occurred in both infected and non-infected cells. The percentages of infected cells, which were apoptotic, ranged between 9 and 39% in the lungs and between 13 and 30% in the BAL cells. The majority of apoptotic cells were non-infected. Non-infected apoptotic cells in the lungs were predominantly monocytes/macrophages, whereas those in the broncho-alveolar spaces were predominantly lymphocytes. The peak of apoptosis in the lungs at 14 days PI was preceded by a peak of IL-1 and IL-10 production at 9 days PI, suggesting a possible role of these cytokines in the induction of apoptosis in non-infected interstitial monocytes/macrophages. However, the latter hypothesis was not confirmed in vitro, since blood monocytes or alveolar macrophages did not undergo apoptosis after treatment with recombinant porcine IL-1 or IL-10.     

A retrospective survey of hydatidosis in livestock in Arusha,Tanzania, based on abattoir data during 2005 - 2007

A 3-year (2005–2007) retrospective study was carried out to investigate the occurrence of cystic echinococcosis (CE) in cattle and shoats (sheep and goats) slaughtered at Arusha municipal abattoir, Tanzania. A total of 115186 cattle and 99401 shoats were slaughtered. Cattle liver, lungs, spleen and heart condemnation rate was 16.35%, 13.04%, 2.09% and 3.06% respectively while 17.63%, 7.63%, 0.38% and 0.04% of shoats’ liver, lungs, spleen and heart respectively were condemned. A highly significant (p < 0.001) cystic echinococcosis (CE) infection rate was recorded in shoats (6.02%) than in cattle (4.2%) probably because of differences in grazing patterns. Cattle lungs were more affected by CE (22.5%) than liver (19.7%) while shoats liver were found to be more affacted (21%) than the lungs (19.3). A significant (p < 0.001) higher CE infection rate was observed in cattle spleen (15.5%) than shoats (9.7%). There was no significant (p > 0.05) difference between condemnation rates due to hydatidosis during rain and dry seasons probably because of chronicity of the disease. The study have established that CE is prevalent in animals slaughtered at Arusha abattoir and causes higher condemnation rates of edible offals. This merit for more extensive epidemiological investigations to better determine the prevalence, economic impact and public health importance of the disease in the region.     

Epidemiological study of the cystic echinococcosis in Morocco

The objectives of this epidemiological study on cystic echinococcosis (CE) in Morocco (2001-2004) were to update the prevalence of CE in different animal species living in the most important areas of the country and to collect protoscoleces and germinal layers for genetic research purposes. The post mortem inspection concerned 2948 sheep, 2337 goats, 618 cattle, 482 camels and 455 equines (325 horses, 60 mules and 70 donkeys) in five different regions: the Rif (Mediterranean coast and high mountains of the Rif), the Loukkos (Atlantic northwest plain), the center (Rabat and Casablanca regions), the Middle Atlas mountains and the south (arid and semi desert areas). The global CE infection prevalence rates obtained were 22.98% in cattle, 10.58% in sheep, 12.03% in camels, 17.80% in equines and 1.88% in goats. The infection rates were especially high in the Middle Atlas in cattle (48.72%) and in the Loukkos in cattle and sheep (37.61 and 31.65%, respectively). The majority of infected cattle (49.6%) and sheep (52.1%) had hydatid cysts in both liver and lungs. Except for cattle, the liver was more infected than lungs in all the other animal species. Animals more than 5 years old were the most infected in all species. The mean CE infection rates of these animals were about 56% in cattle, 40% in sheep, 20% in camels, 17.80% in equines and 7% in goats. These rates were much higher in the Loukkos (85% of cattle and 59% of sheep) and in the Middle Atlas (68% of cattle and 45% of sheep) than in the other regions. Results showed that Echinococcus granulosus is in an endemic steady state with no evidence of protective immunity in the intermediate hosts. The mean numbers of infections per year are 0.099 for cattle, 0.063 for sheep, 0.03 for camels and 0.010 for goats.     

Lymphosarcoma in 10 New World Camelids

We evaluated the medical information from 10 New World Camelids with lymphosarcoma. Additionally, tumor tissue from 5 animals was examined by electron microscopy for evidence of retroviral particles. Lymphosarcoma was the most common neoplasm of New World Camelids in our hospital. Both llamas and alpacas, from 4 months to 15 years of age, were affected. Emaciation (7 of 8) and palpable masses (9 of 10) were the most common physical examination abnormalities, and a left-shifted leukogram (7 of 7) and hypoalbuminemia (6 of 7) were the most characteristic clinicopathologic findings. Lymphosarcoma was diagnosed by lymph node aspirate (n = 2), biopsy (n = 2), peritoneal fluid analysis (n = 2), or necropsy (n = 4). The clinical course after recognition of the disease was usually short, with a median survival of 1 month (1 week to 3 months). Organs with neoplastic infiltrates commonly included lymph nodes (n = 8), liver (n = 8), kidneys (n = 6), and lungs (n = 5). No retroviral particles were detected ultrastructurally.     

Bovine viral diarrhea viral infections in feeder calves with respiratory disease: interactions with Pasteurella spp., parainfluenza-3 virus, and bovine respiratory syncytial virus.

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in a group of stocker calves suffering from acute respiratory disease. The calves were assembled after purchase from Tennessee auctions and transported to western Texas. Of the 120 calves, 105 (87.5%) were treated for respiratory disease. Sixteen calves died during the study (13.3%). The calves received a modified live virus BHV-1 vaccine on day 0 of the study. During the study, approximately 5 wk in duration, sera from the cattle, collected at weekly intervals, were tested for BVDV by cell culture. Sera were also tested for neutralizing antibodies to BVDV types 1 and 2, bovine herpesvirus-1 (BHV-1), parainfluenza-3 virus (PI-3V), and bovine respiratory syncytial virus (BRSV). The lungs from the 16 calves that died during the study were collected and examined by histopathology, and lung homogenates were inoculated onto cell cultures for virus isolation. There were no calves persistently infected with BVDV detected in the study, as no animals were viremic on day 0, nor were any animals viremic at the 2 subsequent serum collections. There were, however, 4 animals with BVDV type 1 noncytopathic (NCP) strains in the sera from subsequent collections. Viruses were isolated from 9 lungs: 7 with PI-3V, 1 with NCP BVDV type 1, and 1 with both BVHV-1 and BVDV. The predominant bacterial species isolated from these lungs was Pasteurella haemolytica serotype 1. There was serologic evidence of infection with BVDV types 1 and 2, PI-3V, and BRSV, as noted by seroconversion (> or = 4-fold rise in antibody titer) in day 0 to day 34 samples collected from the 104 survivors: 40/104 (38.5%) to BVDV type 1; 29/104 (27.9%) to BVDV type 2; 71/104 (68.3%) to PI-3V; and 81/104 (77.9%) to BRSV. In several cases, the BVDV type 2 antibody titers may have been due to crossreacting BVDV type 1 antibodies; however, in 7 calves the BVDV type 2 antibodies were higher, indicating BVDV type 2 infection. At the outset of the study, the 120 calves were at risk (susceptible to viral infections) on day 0 because they were seronegative to the viruses: 98/120 (81.7%), < 1:4 to BVDV type 1; 104/120 (86.7%) < 1:4 to BVDV type 2; 86/120 (71.7%) < 1:4 to PI-3V; 87/120 (72.5%) < 1:4 to BRSV; and 111/120 (92.5%) < 1:10 to BHV-1. The results of this study indicate that BVDV types 1 and 2 are involved in acute respiratory disease of calves with pneumonic pasteurellosis. The BVDV may be detected by virus isolation from sera and/or lung tissues and by serology. The BVDV infections occurred in conjunction with infections by other viruses associated with respiratory disease, namely, PI-3V and BRSV. These other viruses may occur singly or in combination with each other. Also, the study indicates that purchased calves may be highly susceptible, after weaning, to infections by BHV-1, BVDV types 1 and 2, PI-3V, and BRSV early in the marketing channel.