Mycoplasma suis in the State of São Paulo: epidemiology and hematology

Author(s)

Nathan Da Rocha Neves Cruz

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2019-12-16.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2019-12-09
• Advisor: Aureo Evangelista Santana; Marcos Rogério André; Luís Guilherme de Oliveira

Abstract

Porcine hemoplasmosis caused by Mycoplasma suis, is characterized as a geographically cosmopolitan disease. It affects animals of various age groups, often associated with moderate to severe hemolytic anemia and predisposes the animals to immunosuppression, infertility, decreased weight gain, increased stillbirths, miscarriages and return to heat, that is, directly impacts pig farms and leads to immeasurable economic losses. From an epidemiological point of view, asymptomatic animals are considered as the focus of hemoplasmosis because they are carriers and present clinical improvement without the elimination of the parasite and some authors report hemotrophic mycoplasmosis as a zoonotic potential disease. The prevalence in Brazilian herds is debatable, especially since the traditional diagnosis by observing M suis in the blood smear has low sensitivity. The objective of this study was to characterize the prevalence rate and correlate the quantity of Mycoplasma suis quantified by qPCR with changes in hematological parameters in pigs in different phases of rearing of full-cycle farms in the State of São Paulo. Twenty different complete cycle swine farms located in the state of São Paulo were evaluated, 501 whole blood samples were collected in EDTA-K2 for molecular analysis of qPCR for Mycoplasma suis and blood count and blood smear hemoparasites. In the first chapter there was a literature review on Mycoplasma suis, the pathobiology of the agent as well as clinical signs in animals. In Chapter 2, the occurrence of Mycoplasma suis was reported in the full-cycle technicated farms in the State of São Paulo and it was possible to determine a total prevalence of infected animals of 31.93% (161/201) and 95% (19/20) infected farms and by growth stages were: nursery (30.47%); growing (31.29%), finishing (26.18%) and slaughter (40.25%). In Chapter 3, the results of the hematological parameters were correlated with the M suis bacteremia, and in the comparison of the blood counts of positive and negative animals there was no statistical difference and both groups did not present alterations values in relation to the adopted reference values. This situation evidences the condition of apparently healthy carriers that help in the permanence and propagation of the agent in the herds. In positive animals, a correlation was observed between hemoglobin (y = 9.978 + 0.186 x, p = 0.02, r² = 0.354), platelets (y = 582.522 - 16.190 x, p = 0.04, r² = 0.286) and neutrophils (y = 9.77 - 0.307 x, p = 0.05, r² = 0.276) with M suis bacteremia, these results indicate the presence of hemolysis, vascular damage and platelet consumption inherent in animals with hemotrophic mycoplasmosis. Keywords: Mycoplasmose, swine, haemoplasma, prevalence, bacteremia, growth stages (AU)

• FAPESP's process: 16/14838-4 - epidemiological and haematological variables mycoplasmosis hemotropic (M. suis) in pigs of São Paulo, Brazil
• Grantee: Nathan da Rocha Neves Cruz
• Support Opportunities: Scholarships in Brazil - Doctorate