Porcine hemothropic mycoplasmas infection associated with productive impact in intensive pig production.

BACKGROUND: So far, three porcine hemoplasmas (PH) have been identified, namely Mycoplasma suis, Mycoplasma parvum, and Mycoplasma haemosuis. The first one is the main agent associated with porcine hemoplasmosis, a possible cause of economic losses in pig production. Thus, this work aimed to detect and quantify PH 16S rRNA in finishing pigs and to associate its load estimate with average daily weight gain (ADWG). For this purpose, whole blood samples from 318 pigs were collected at an age of 75 days (d0) when the pigs entered the finishing phase and 105 days later (d105). To calculate ADWG, the animals were weighed at the abovementioned dates. Then, DNA from blood samples were submitted to a qPCR targeting the 16S rRNA gene for PH. Spearman correlation test was performed to investigate potential associations between ADWG and the quantification values. Lastly, the molecular characterization of PH was done by sequencing the 23S rDNA gene. RESULTS: Out of the 318 samples, 190 (59.74%) were positive on d0, and 304 (95.6%) were positive on d105. A significant correlation was observed (p < 0.05), albeit with a low coefficient value (0.18), when comparing ADWG with quantification values on d105. The phylogenetic analysis based on the 23S rDNA gene showed that four sequences were closely related to M. parvum, and one sequence was positioned in the M. suis cluster. CONCLUSION: Two PH, M. suis and M. parvum, were detected in a Brazilian pig farm. Moreover, increasing occurrence through time was observed, which may have affected the productive performance of positive animals, mainly at the end of the finishing phase, when antimicrobials are removed.

Cross-sectional study of Leptospira spp. in commercial pig farms in the state of Goiás, Brazil.

Leptospirosis is an infectious, contagious disease highly important to the world pig industry, which causes reproductive loss in breeding herds. Endemic infections in a herd may produce little evidence of clinical disease despite resulting in economic losses. However, some epidemiological features of leptospirosis in midwestern Brazil, such as risk factors and prevalence of the disease, remain unclear. Therefore, this study focused on assessing the prevalence of the Leptospira spp. in intensive pig herds and associating its risk factors. A set of 900 blood samples, equally distributed between nursery, growing, and finishing pigs of 30 intensive farrow-to-finish farms, were analyzed using the microagglutination test (MAT), in order to detect anti-Leptospira spp. antibodies for 24 different Leptospira spp. serovars. An occurrence of 4.67% (55/342) seropositive samples were detected in fattening pigs. The variables associated with the disease occurrence were animals per square meter at fattening (OR 0.006, CI 95% 0.004-0.42, p = 0.0105) and pen division between growing and fattening pigs (OR 3.56, CI 95% 0.563-22.541, p = 0.185). Thus, the variables semi-hollow floor in the maternity (OR 16.66; CI 95%: 2.17-128.2 and p = 0.006) and animals per trough at fattening (OR: 0.08, CI 95% 0.009-0.87 and p = 0.025), observed in this study, highlight the importance of the fattening phase in the epidemiology of the disease, bringing information on risk factors involved in the occurrence and dissemination of leptospirosis in intensive pig herds.

Epidemiology of bovine cysticercosis and associated economic losses in the state of Rio Grande do Sul, Brazil.

Bovine cysticercosis (BCC) is the most frequently detected zoonosis in Brazilian slaughterhouses and is considered a problem for public health and beef production chain, requiring epidemiological studies focusing on evaluating its prevalence, spatial distribution, and economic losses in order to improve and adopt specific strategies for BCC control. Thus, this study focused to establish BCC prevalence and spatial distribution in the state of Rio Grande do Sul, Brazil, and estimate the economic losses for cattle farmers suppliers of one exporter slaughterhouse. A set of 70,591 bovine carcasses were postmortem inspected from 2019 to 2020, which came from 134 municipalities located in eight distinct regions in the state of Rio Grande do Sul. The prevalence found was 3.44% (C.I. 95% 3.30-3.57%), and animals infected with unviable cysticerci were more frequently detected (70.56%) than those carrying viable ones (29.44%). The most frequent destination of carcasses and viscera was non-export (65.48%), followed by freezing/salting (25.41%), heat treatment (8.74%), and rendering (0.37%), resulting in a total economic burden of at least US$ 167,868.53 for cattle farmers. Some regions had higher risk for BCC occurrence, such as Porto Alegre, Caxias do Sul, Santa Maria, Ijuí, and Passo Fundo (OR > 1, p < 0.05), respectively. These results highlight the need of adopting prophylactic measures, mainly in specific areas, in order to control BCC and reduce the economic losses for beef production chain.

Cross-sectional study of seropositivity, lung lesions and associated risk factors of the main pathogens of Porcine Respiratory Diseases Complex (PRDC) in Goiás, Brazil.

BACKGROUND: The objective of the study was to evaluate the occurrence and severity of Porcine Respiratory Diseases Complex (PRDC) pathogens in the Goiás State, Brazil. Were assessed the serological antibodies occurrency of Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae and swine influenza virus (SIV), as well as the evaluation of pulmonary Mycoplasma-like lung lesions, pleuritis, histopathological lesions and diseases occurrence associated with risk factors, such as management, housing and productive indexes. We conveniently selected 2536 animals for serology testing, and 900 lungs at slaughtering of animals from 30 multisite herds in Goiás State, Brazil. RESULTS: For M. hyopneumoniae, all herds presented seropositive animals at some stage of production. Even though most herds (29/30) vaccinated against this pathogen, 90.0% (27/30) of the herds presented at least 50.0% of seropositive animals in finishing and slaughter. Overall, antibodies against A. pleuropneumoniae were present in lower occurrence, varying from 22.4% of the animals in the nursery phase to 1.3% of the animals at slaughter. Conversely, SIV circulated in most herds, with 29 seropositive herds without vaccination. The occurrence of anti-SIV antibodies was higher at slaughter (74.5% of the animals) than nursery (41.8% of the animals), and at slaughter, 23 herds (76.7%) presented at least 50.0% of seropositive animals. All herds presented animals with pulmonary Mycoplasma-like lung lesions, and of the 900 lungs evaluated in the slaughterhouse, 665 (73.9%) presented an average Mycoplasma-like lung lesions of 7.3%. Evaluations of the pneumonia index (PI) showed that 73.3% of the herds were strongly affected by a pathology that manifested itself in different presentation forms. Microscopically, there was a predominance of bronchopneumonia lesions (74.6% of affected lungs), with a high occurrence of the chronic form (57.1%), and there was a moderate to marked proliferation of bronchial associated lymphoid tissue (BALT) in 64.1% of the affected lungs. Pleuritis were observed in 13.5% of the animals. CONCLUSION: Serological tests evidenced that antibodies against App and SIV were present in the Goiás State herds, and high occurrence of M. hyopneumoniae antibodies in finishing phases and slaughter may be influenced by pathogen circulation in vaccinated herds, leading to respiratory lesions at slaughter. Additionally, swine influenza virus was broadly disseminated in technified herds in Goiás State.

Prevalence of Toxoplasma gondii infections in swine of non-tecnified rearing farms of the northeastern region of the state of São Paulo, Brazil and associated risk factors.

Toxoplasmosis is a zoonosis present worldwide. Its protozoal aethiological agent, Toxoplasma gondii, has the ability to infect several homeothermic animals and mainly human beings. The consumption of raw or undercooked meat products containing T. gondii cysts, consumption of vegetables without washing and using non-treated water are risk factors associated to the occurrence of human toxoplasmosis. Furthermore, raw or undercooked pork is an important infection source of T. gondii to humans. Due to the importance of toxoplamosis in public health, this study focused on establish the prevalence of the disease in non-technified swine herds in the northeastern region of the State of São Paulo, Brazil, using Modified Agglutination Test (MAT) and the Indirect Immunofluorescence Assay (IFA) and the risk factors for its occurrence. In addition, the agreement among both diagnostic tests was evaluated. A low prevalence of toxoplasmosis was found at animal level (7.02%). The Fisher's exact test detected correlation between positive cases with the presence of food garden in the farm (p = 0.01) and the use of non-treated water to irrigate the food garden (p = 0.005). The agreement among tests was considered moderate (Kappa index = 0.5). The results show that toxoplasmosis is a risk for humans who consume under cooked pork meat in this region and an acceptable agreement between MAT and IFA tests.

Experimental inoculation of gilts with bovine viral diarrhea virus 2 (BVDV-2) does not induce transplacental infection.

Bovine viral diarrhea virus (BVDV) belongs to the genus Pestivirus and can cause reproductive problems in cattle. However, there is still a lack of research to clarify its pathogenicity in different gestational periods of sows and its effects in neonates. In this study, 12 gilts divided into groups (G) were experimentally inoculated with the strain BVDV-2 (SV-253) oronasally at a dose of 106·85 TCID50; one group was inoculated 30 days before insemination (G0; n = 2), three groups were inoculated during gestation (first (G1; n = 2), second (G2; n = 3), third (G3; n = 3)), and a fourth was the control group (G4; n = 2). Samples of blood and nasal swabs from the gilts were collected every three days until delivery for a virus neutralization (VN) test, qRT-PCR, and blood count. On the day of delivery, 40% of the neonates were euthanized to obtain tissue and blood samples at necropsy for histopathology and qRT-PCR. The sows were seroconverted between 12 and 33 days after inoculation, and the virus was detected in the blood between 3 and 12 days and on the nasal swab between 6 and 24 days in the G0, G1, G2 and G3 sows but was not detected in piglet tissues, and no significant alterations were found through histopathology. The mean and standard deviation of the mean cycles (Cq) from blood (Cq = 34.87 ± 0.60) and nasal swab (Cq = 34.61 ± 0.87) samples were between 107 and 490 TCID50/ml. Transient infection was demonstrated with a low viral load, but transplacental infection was not possible in gilts.

Description of risk factors associated with the detection of BVDV antibodies in Brazilian pig herds.

Bovine viral diarrhea virus (BVDV) infects ruminants as primary hosts. However, other animals like pigs are susceptible. This study was conducted to investigate seroprevalence and risk factors associated with the detection of BVDV antibodies in pig herds. A total of 1.705 serum samples of 33 finisher herds, from seven Brazilian states, were collected in slaughterhouses. The samples were tested by virus neutralization (VN) test. In total, 5.35% (91/1.705) were positive and 64% (21/33) of the herds had positive animals. A significant association with "trucks are not cleaned and disinfected" and "visitors do not respect 72-h interval between visits to farms" (P < 0.05) was found in association with detection of BVDV-2 antibodies. This study suggests that important biosecurity gaps are present in Brazilian pig farms, as the presence of BVDV antibodies in pigs suggests (direct or indirect) contact with population(s) of ruminant species. Closing biosecurity gaps prevents spread of BVDV and other pathogens such as foot-and-mouth disease virus (FMDV) between pig and ruminant farms. This data should be taken in account by CSF surveillance programs, once cross-reaction in serologic tests between classical swine fever virus (CSFV) and BVDV antibodies has been shown to occur.

Spatial distribution, prevalence and epidemiological risk factors of cysticercosis in cattle from state of São Paulo, Brazil, slaughtered for human consumption.

This present research focused on establishing the prevalence, geospatial distribution and epidemiological risk factors for bovine cysticercosis in the state of São Paulo, Brazil, in cattle slaughtered for human comsumption. Data about the inspection of 104,180 bovine carcasses from 215 farms and from 70 municipalities were gathered between January and December of 2012. A cluster analysis was performed in order to correlate some variables: prevalence of bovine cysticercosis, total coffee harvesting area (hectares), orange producing areas (hectares) and Human Development Index. Afterwards, distribution maps were created in order to help the results interpretation. An average prevalence of 2.9% was established in the state of São Paulo during the studied period. The Administrative regions of São José do Rio Preto and Campinas had higher risk for cysticercosis (OR >1 and 95% CI >1). The cluster analysis showed a grouping (G1 cluster) of the variables: prevalence of bovine cysticercosis, total area of sugar cane harvested, total area of orange harvested and total area of coffee harvested. This agrroupment allows us to infer that cyticercosis cases in this region are correlated with those variables distribution. Such aspects indicate that the presence of temporary rural workers and other socioeconomic and cultural features in each region can contribute to bovine cysticercosis dissemination in some areas.