Risk factors associated with the frequency of antibodies against Babesia bovis and Babesia bigemina in cattle in southern Mozambique

The study aimed to evaluate the risk factors associated with the frequency of IgG antibodies against Babesia bovis and B. bigemina in cattle in southern Mozambique. Eight hundred and nine serum samples were collected from cattle in three provinces namely Maputo, Gaza and Inhambane, and tested by indirect enzyme-linked immunosorbent assay (i-ELISA) to assess the humoral immune response towards B. bovis and B. bigemina. The chi-square test at 5% significance was used to determine whether there was an association between gender, age and geographic origin of seropositive animals. The overall prevalence was 78.8% (548/695) for B. bovis and 76.0% (528/695) for B. bigemina. The origin of the animals showed a significant association (p<0.05) with seropositivity to both agents, while gender and age was not associated (p>0.05). Maputo province had the highest rate of positive animals, with 93.7% (118/126) for B. bovis and 97.6% (123/126) for B. bigemina. In Gaza province 77.3% (321/415) of the animals were positive for B. bovis and 67.5% (280/415) for B. bigemina, while in the province of Inhambane the levels of seropositivity were 70.8% (109/154) and 81.2% (125/154) for B. bovis and B. bigemina respectively. In the present study, the frequency of cattle positive for B. bovis and B. bigemina was shown to increase among older age groups, suggesting that infection and re-infection persisted even after the primary infection. Thus, this region is considered to be in a state of enzootic stability with regards to B. bovis and B. bigemina.

Spinal cord compression in cattle after the use of an oily vaccine

An outbreak of compressive myelopathy in cattle associated with the improper use of an oil vaccine is described. Neurological signs were observed in 25 out of 3,000 cattle after 60 days of being vaccinated against foot and mouth disease. The clinical picture was characterized by progressive paralysis of the hind limbs, difficulty in standing up, and sternal recumbency during the course of 2-5 months. A filling defect between the L1 and L3 vertebrae was seen through myelography performed in one of the affected animals. A yellow-gray, granular and irregular mass was observed in four necropsied animals involving the spinal nerve roots and epidural space of the lumbar (L1-L4) spinal cord; the mass was associated with a whitish oily fluid. This fluid was also found in association with necrosis of the longissimus dorsi muscle. Microscopic changes in the epidural space, nerve roots, and spinal musculature were similar and consisted of granulomas or pyogranulomas around circular unstained spaces (vacuoles). These spaces were located between areas of severe diffuse hyaline necrosis of muscle fibers and resembled the drops of oil present in the vaccine.

Prevalence and risk factors for Leptospira spp. in cattle herds in the south central region of Paraná state

The aim of this study was to determine the prevalence of anti-Leptospira spp. antibodies and the risk factors for Leptospira spp. infection in breeding cattle herds in the south central region of Paraná state. It was based on the statistic delineation/serological samples and information regarding the selected farms employed in the study of bovine brucellosis for Paraná state in the context of National Program for Control and Eradication of Brucellosis and Tuberculosis. A total of 1.880 females aged >24 months from 274 non vaccinated herds were studied. Serum samples were tested for antibodies against Leptospira spp. using microscopic agglutination test (MAT) with 22 Leptospira serovars. The epidemiological questionnaire was applied on all the selected farms and aimed to obtain epidemiological data. Hundred eighty one of 274 herds were positive for Leptospira spp./presenting prevalence of positive herds of 66.06% (IC95%=60.12-71,65%). Presence of >43 cattle (OR=3.120; IC=1.418-6.867)/animal purchase (OR=2.010; IC=1.154-3.500)/rent of pastures (OR=2.925; IC=1.060-8.068) and presence of maternity paddock (OR=1.981; IC=1,068-3,676) were identified as risk factors for leptospirosis due to any serovar in the multivariate logistic regression. Risk factors for leptospirosis due to serovar Hardjo were presence of >43 cattle (OR=3.622; IC=1.512-8,677)/animal purchase (OR=3.143; IC=1.557-6.342)/rent of pastures (OR=4.070; IC=1.370-12.087) and presence of horses (OR=2.981; IC=1.321-6.726). These results indicate that Leptospira spp. infection is widespread in the south central region of Paraná state and that factors related to the herd characteristic and management are associated with the infection.

Pathological findings in fetuses of goats and cattle poisoned by Sida carpinifolia (Malvaceae)

In Brazil, the consumption of Sida carpinifolia by livestock has been associated with neurological diseases linked to lysosomal storage disorders. This paper describes the pathological findings in two caprine fetuses from dams that were experimentally poisoned with S. carpinifolia. The goats were orally dosed with 10 and 13g/kg of a paste of green chopped S. carpinifolia for 30 days and were observed for an additional 15 days period after the last dosage with the plant; thereafter they were euthanized and necropsied. The dams showed only slight clinical signs. The study also includes the findings in one bovine fetus from a naturally S. carpinifolia poisoned cow which showed mild incoordination, generalized tremors, staggering, and frequent falls. The cow was euthanized and necropsied. While there were no significant histopathological changes in the goats, in the cow vacuolation of Purkinje neurons of the cerebellum, pancreatic acinar cells, and thyroid follicular cells were observed. The main microscopic changes observed in the caprine and bovine fetuses were vacuolation in the epithelium of renal tubules, thyroid follicular cells, and Purkinje neurons of the cerebellum. Transmission electron microscopy of sections from CNS of the cow and its fetus revealed vacuoles containing fine granular material surrounded by membrane. Lectin-histochemistry of CNS sections from goat fetuses marked lightly to sWGA lectins, WGA, and Con-A.

Impact of ivermectin-resistant gastrointestinal nematodes in feedlot cattle in Argentina

The aim was to evaluate for 75 days the impact on production of the remaining burden of ivermectin (IVM)-resistant parasites in naturally infected feedlot calves. The herds came from tick-infested areas of cattle breeding where the systematic use of IVM to control tick increases the gastrointestinal parasites resistant to this drug. This investigation was carried out in two commercial feedlots in Buenos Aires province. In feedlot A, two groups of 35 animal each received IVM 1% and the other received ricobendazole (RBZ) 10% respectively. The same was done in feedlot B. On day 0, two groups of 35 animals were made in feedlots A and B. Fecal samples were taken on days 0, 22, 54 and 75 pos-treatment (PT), and body weight was registered, from each animal. Fecal samples were processed for individual count of eggs per gram (EPG) and pooled fecal culture was carried out for identification of the parasite genus in each sampling. Fecal egg count reduction test (FECR) was calculated on day 22 PT. The study design used was a totally randomized block, with commercial feedlot and sex as block variables. For data analysis, a mixed model of the SAS statistical program was used. The FECR average on day 22 was 28.4% in the IVM group, and 94,2 % in the RBZ group . From this date on, significant differences in EPG were kept until day 54. EPG counts were only equal near the end of the trial, on day 75 (p=0.16). In both commercial feedlots, especially in the IVM group, Cooperia spp. was the most prevalent parasite in the fecal cultures. Significant differences in weight (P<0.01) on post-treatment day 75 was found between the average weight in the RBZ and the IVM group (246 vs. 238 kg respectively), what means a difference of 8.3% in gains. The importance for production in the antiparasite failure treatment in commercial feedlots was demonstrated, and the need of pos-treatment controls to evaluate the efficacy of the antiparasitic administered is emphasized.

Decreased expression of cardiac troponin C is associated with cardiac lesions in Amorimia exotropica poisoned cattle

The plants which cause sudden death of cattle in Brazil occupy a leading position for losses in the cattle industry. Amorimia exotropica is one of the plants pertaining to this group. Diagnostic findings in these cases may be inconclusive; further knowledge is necessary. This paper identifies cardiac lesions through anti-cardiac troponin C (cTnC) immunehistochemistry performed in tissues from cattle poisoned after consumption of A.exotropica in southern Brazil. Heart fragments from nine A. exotropica-poisoned cattle were studied immunohistochemically using anti-human cTnC as the primary antibody. In the hearts from all of the poisoned cattle, there was a sharp decrease in the cTnC expression level in the cytoplasm of groups of cardiomyocytes. A significant decrease in anti-cTnC immunoreactivity occurred particularly in degenerated or necrotic cardiomyocytes. Occasional groups of cells showed complete loss of immunolabeling. In the remaining intact cardiomyocytes from poisoned cattle and in cardiomyocytes from six cattle that died from other causes there was intense cytoplasmic staining.

Seroprevalence and risk factors associated with infection by Neospora caninum of dairy cattle in the state of Alagoas, Brazil

The objective of this study was to investigate the prevalence of anti-Neospora caninum antibodies in cattle from milk producing farms of the microregion of Batalha, state of Alagoas, Brazil, as well as to identify the risk factors associated with the infection. Blood samples were collected from 1,004 cattle of 17 farms for the serological investigation regarding the presence of anti-N. caninum antibodies by the Indirect Immunofluorescence Reaction Technique (IMRT). From the total amount of samples analyzed, 77/1,004 (7.67%) were positive and 927/1,004 (92.33%) were negative. The logistical regression identified that cattle from farms without consortium breeding have an infection risk 6.33 (p<0.001; C.I. 2.89-13.10) times higher than cattle from farms with that type of breeding. Cattle from farms where the aborted fetuses are not adequately buried have an infection risk 3.04 (p<0.001; C.I. 1.64-5.63) times higher than cattle from farms with adequate destination of these fetuses. Infection by N. caninum occurs in cattle of the investigated region. The factors identified in our study can be used as risk indicators, so that control measures could be implemented to avoid infection by N. caninum in the herds of this region.

Sawfly larval poisoning in cattle: Report on new outbreaks and brief review of the literature

Sawfly larval poisoning (SLP) is an acute hepatotoxicosis documented in livestock in Australia, Denmark and in countries of South America. It is caused by the ingestion of the larval stage of insects of the suborder Symphyta, order Hymenoptera, commonly known as "sawfly". Three species of sawfly are reportedly involved in the toxicosis. The insect involved in Australian SLP is Lophyrotoma interrupta (Pergidae), in Denmark the cause of SLP is the ingestion of the larvae Arge pullata (Argidae), and in South American countries documented outbreaks of SLP were caused by the ingestion of yet another sawfly, Perreyia flavipes (Pergidae). In all geographical areas where it occurred, SLP causes important livestock losses. In cattle, as well as in other affected species, the disease has a short clinical course and in many outbreaks affected cattle can be found dead. When observed, clinical signs include apathy, recumbence, tremors, paddling movements and death in 24-48 hours. Neurological signs such aggressiveness attributable to hepatic encephalopathy are also observed. In cases with a more protracted course icterus and photodermatitis may develop. Gross findings included ascites, petechiae and ecchymosis over serosal surfaces of thoracic and abdominal cavities, and an enlarged liver that displays accentuation of the lobular pattern and edema of the gall bladder wall. Sawfly larval body fragments and heads are consistently found in the fore stomachs and occasionally abomasum of affected cattle. Main microscopic lesions are restricted to the liver and consist of centrolobular (periacinar) to massive hepatocellular necrosis. In most lobules necrotic areas extended up to the portal triads where only a few viable hepatocytes remain. Mild to moderate lymphocyte necrosis is seen in lymphatic tissues. Cases occur in the winter months when the larval stages of the sawfly are developing. D-amino acid-containing peptides have been found to be the toxic principle in each sawfly involved in SLP. The octapeptide lophyrotomin is the major toxin in the in the larvae of Australian and Danish sawflies and is present in small amounts in the larvae of South American sawfly. The heptadecapeptide pergidin is the main toxin in the South American sawfly while small amounts of pergidin have been found in the other two species of toxic sawfly. During the winter of 2011 (July-August) four outbreaks of SLP were diagnosed in the State of Rio Grande do Sul, Brazil. The findings in those outbreaks are reported here and a brief review of the literature regarding SLP around the world is provided.

Molecular confirmation of ovine herpesvirus 2-induced malignant catarrhal fever lesions in cattle from Rio Grande do Norte, Brazil

Molecular findings that confirmed the participation of ovine herpesvirus 2 (OVH-2) in the lesions that were consistent with those observed in malignant catarrhal fever of cattle are described. Three mixed-breed cattle from Rio Grande do Norte state demonstrated clinical manifestations that included mucopurulent nasal discharge, corneal opacity and motor incoordination. Routine necropsy examination demonstrated ulcerations and hemorrhage of the oral cavity, corneal opacity, and lymph node enlargement. Significant histopathological findings included widespread necrotizing vasculitis, non-suppurative meningoencephalitis, lymphocytic interstitial nephritis and hepatitis, and thrombosis. PCR assay performed on DNA extracted from kidney and mesenteric lymph node of one animal amplified a product of 423 base pairs corresponding to a target sequence within the ovine herpesvirus 2 (OVH-2) tegument protein gene. Direct sequencing of the PCR products, from extracted DNA of the kidney and mesenteric lymph node of one cow, amplified the partial nucleotide sequences (423 base pairs) of OVH-2 tegument protein gene. Blast analysis confirmed that these sequences have 98-100% identity with similar OVH-2 sequences deposited in GenBank. Phylogenetic analyses, based on the deduced amino acid sequences, demonstrated that the strain of OVH-2 circulating in ruminants from the Brazilian states of Rio Grande do Norte and Minas Gerais are similar to that identified in other geographical locations. These findings confirmed the active participation of OVH-2 in the classical manifestations of sheep associated malignant catarrhal fever.

Clinical aspects and dynamics of auricular parasitosis in Gir cattle

We evaluated the dynamics of ear infestations caused by Rhabditis spp. and Raillietia spp., which were correlated with animal age, intensity of clinical signs and climate factors. Sixty-four Gir cattle were distributed into three groups: GA - 23 calves with 4 to 6 months of age; GB - 18 calves with 7 to 12 months of age; and GC - 23 heifers with 13 to 33 months of age. Five samplings, defined as S1, S2, S3, S4 and S5 were performed every three months from August 2008 to August 2009. The ear secretion was collected using the auricular washing method for the right ear and a swab for the left ear. A clinical assessment of the animals was performed, and they were classified according to the presence and severity of otitis. The highest relative frequency of rhabditosis was 52.2% in GC at the last sampling. In the first sampling, 42.2% of the animals were infested by Raillietia spp. The older cattle were more susceptible to infestations by both parasites. No correlation of Rhabditis spp. and Raillietia spp. parasitism with climate factors was found. The results showed that both parasites could infest Gir cattle, and in most cases, there was no co-infestation. Only older animals parasitized by the nematode showed clinical signs of the disease.

Epidemiological survey of the taeniasis/cysticercosis complex in cattle farms in Viçosa County, Minas Gerais, Brazil

Despite the importance of human taeniasis/bovine cysticercosis for public and animal health and the economy, its actual epidemiological status in Brazil is not well-studied. We sought to assess the epidemiological profile of this zoonosis in the rural area of Viçosa County, Minas Gerais, Brazil. The prevalence of bovine cysticercosis was 0.42%, whereas no case of human taeniasis was diagnosed. Factors favoring the persistence of zoonosis were identified. These included the supply of untreated water to animals, animals raised for slaughter without sanitary supervision, poor mechanization of raising techniques, and the use of untreated water for human consumption. Bovine meat for human consumption acquired in the city or from the farm itself was characterized as a risk factor for bovine cysticercosis (Odds Ratio (OR) =16.77; p<0.05). Nevertheless, the families on the investigated farms did apply several appropriate measures to control this disease, such as the virtual lack of open sewers and the consumption of well-cooked meat. The presence of bovine cysticercosis cases, and the factors favoring its persistence, point to the need for constant epidemiological and sanitary surveillance in this county.

Acute fasciolosis in cattle in southern Brazil

This study describes the epidemiological and pathological aspects of an outbreak of acute fasciolosis in cattle in southern Brazil. Fifteen out of 70 three-year-old pregnant cows lost weight in the 30-40 days prior to calving. Clinical signs included diarrhea, weakness, mild anemia and jaundice. Dark yellow fluid in the abdominal cavity was observed at necropsy. Fibrin and clotted blood were adhered to the pericardium and lung, primarily in the diaphragmatic lobes. The liver was enlarged, and the capsular surface was irregular with clear areas and petechiae. At the cut surface, the liver was irregular, firm and edematous, and several hemorrhagic channels could be observed. Areas of fibrosis through the parenchyma and whitish thrombi occluding the great vessels were also observed. The livers of 10 cows that not died were condemned at slaughter for lesions of fasciolosis similar to those observed at necropsy. Microscopically, the liver showed areas of coagulation necrosis, extensive hemorrhages in the streaks or foci and disruption of the parenchyma with neutrophil and eosinophil infiltration. Fibrosis and bile duct proliferation were also observed. Immature Fasciola hepatica flukes were observed in the parenchyma surrounded by degenerated hepatocytes, neutrophils, eosinophils, and hemorrhages. The outbreak occurred on a farm located in an area endemic for fasciolosis, although the acute form of the disease is not common in cattle in this region. It is likely that the cows were infected by F. hepatica metacercariae released in the late fall or early spring in the rice stubble where the herd was grazing prior to calving. Although mortality due to fasciolosis in cattle is infrequent, outbreaks can occur and treatments that are effective in both the immature and adult forms of the parasite should be administered to prevent economic losses.

Outbreaks of vesicular disease caused by Vaccinia virus in dairy cattle from Goiás State, Brazil (2010-2012)

Cases of vesicular and exanthematic disease by Vaccinia virus (VACV) have been reported in dairy herds of several Brazilian regions, occasionally also affecting humans. The present article describes eight outbreaks of vesicular disease caused by VACV in dairy herds of six counties of Goiás state, Midwestern Brazil (2010-2012), involving a total of 122 cows, 12 calves and 11 people. Dairy cows (3 to 9 years old) were affected in all cases and calves (2 to 9 months old) were affected in five outbreaks, presenting oral lesions. The morbidity ranged between 8 and 100% in cows, and 1.5 to 31% in calves. In the cows, the clinical signs started with vesicles (2-7mm), painful and coalescent papules (3-8 mm), which resulted in ulcers (5-25mm) and scabs in teats, and, occasionally, in the muzzle. The clinical course lasted from 16 to 26 days. The histopathology of bovine skin samples revealed superficial perivascular inflammatory infiltrate of lymphocytes, plasma cells, neutrophils, macrophages and multifocal areas of acanthosis, spongiosis, hipergranulosis and parakeratotic or orthokeratotic hyperkeratosis with adjacent focally extensive ulcers. Eosinophilic inclusion bodies were noted in the cytoplasm of the keratinocytes. PCR to vgf gene of Orthopoxvirus was positive in samples collected from all outbreaks, and in some cases, genomic VACV sequences were identified by nucleotide sequencing of the PCR amplicons. Infectious virus was isolated in cell culture from scabs from one outbreak. Antibodies to Orthopoxvirus were detected in at least 3 or 4 animals in most outbreaks, by ELISA (outbreaks 1, 2, 3, 4, 5 and 7) or virus-neutralization (outbreak 6). Neutralizing titers ranging from 8 to 64 in outbreak 6. In all outbreaks, VACV infection was suspected based on the clinical and pathological findings and it was confirmed by laboratory tests. Upon the etiological confirmation, other agents associated with vesicular disease were discarded. In all outbreaks, at least one milker who handled the affected cows developed malaise, headache, fever, painful vesico-pustular lesions mainly in the hands, but also in the neck and nose. These results confirm the circulation of VACV in the region and call attention for a correct diagnosis and the adoption of prophylactic and control measures.

Babesiosis and anaplasmosis in dairy cattle in Northeastern Brazil

The goal of this study was to characterize the epidemiological situation and the factors involved in the prevalence of babesiosis and anaplasmosis in cattle in the dairy basin of Parnaíba, Piauí, Brazil. The study was conducted in 22 farms, and collected blood samples from 202 cattle to study serological, molecular and determination of the packed cell volume (PCV). On the farms were applied surveys involving epidemiological aspects. Seroprevalence rates were: Babesia bigemina 52.5%, B. bovis 68.8%, and Anaplasma marginale 89.1%. Of the samples analyzed, 73.3% were reactive for Babesia spp. and A. marginale, showing co-infection. In PCR, B. bigemina and B. bovis were positive in 52.0% and 33.2% respectively, and A. marginale in 76.2%. Of these, 51.5% amplified DNA of Babesia spp. and A. marginale. The semi-intensive management predominated in 68.0% of the farms studied. The clinical history of babesiosis and anaplasmosis, was reported from 73% of the farms. There was no significant difference (p>0.05) between age groups and for the PCV of positive compared with negative animals. The study indicates that in this region is enzootic instability for babesiosis and enzootic stability for anaplasmosis, reinforcing the fact that in Brazil there are areas of enzootic instability, even in tropical regions of the country. The PCR technique was a valuable tool for the diagnosis of these diseases and may be used to characterize a geographic region.

Enterohemorrhagic Escherichia coli O157: H7 from healthy dairy cattle in Mid-West Brazil: occurrence and molecular characterization

Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 represents the major Shiga toxin-producing E. coli (STEC) strain related to large outbreaks and severe diseases such as hemorrhagic colitis (HC) and the potentially lethal hemolytic uremic syndrome (HUS). The aim of this study was to report the occurrence and molecular characterization of O157:H7 isolates obtained by rectal swab from 52 healthy dairy cattle belonging to 21 farms in Mid-West of Brazil. Detection of 16SrRNA, stx1, stx2, rfbO157, fliCh7, eae, ehxA, saa, cnf1, chuA, yjaA and TSPE4.C2 genes was performed by PCR. The isolates were further characterized by serotyping. Two hundred and sixty E. coli isolates were obtained, of which 126 were characterized as STEC. Two isolates from the same cow were identified as serotype O157:H7. Both isolates presented the stx2, eae, ehxA, saa and cnf1 virulence factor genes and the chuA gene in the phylogenetic classification (virulent group D), suggesting that they were clones. The prevalence of O157:H7 was found to be 1.92% (1/52 animals), demonstrating that healthy dairy cattle from farms in the Mid-West of Brazil are an important reservoir for highly pathogenic E. coli O157:H7.