Diseases of the central nervous system in swine in Southern Brazil

ABSTRACT: Brazil is the fourth largest exporter of pork worldwide, with its production concentrated in the Southern region of the country. To reduce the economic impacts and increase herd health, an efficient diagnosis of diseases is necessary. The frequency, seasonal, and annual distribution of diseases that affecting the swine nervous system in Southern Brazil were determined through a retrospective study conducted from 2008 to 2018. A total of 231 pigs were evaluated, and distributed in the following phases: suckling piglets, nursery, growing, finishing, and adults. Piglets in the nursery phase were the most affected with 58.01%. Infectious diseases accounted for 87.01% (201/231) of lesions in the nervous system. Bacterial meningitis was observed in 58.87% of cases, presenting an endemic distribution, and a propensity to occur in the months of autumn/winter. The highest number of cases of porcine circovirus-2 were observed in 2008 and 2009, with a subsequent decline. Porcine circovirus, salt poisoning, and brain abscesses exhibited no association between the seasonal occurrence and annual distribution. Salt poisoning was observed more frequently in the last years of this study. Both, non-suppurative encephalomyelitis and selenium toxicosis exhibited an association between their occurrence and seasonal distribution in, the months of winter, and summer, respectively.

Outbreak of salt poisoning in goats in the state of Pará, Brazil

The present study reports two outbreaks of salt poisoning in goats on a property in the state of Pará, Brazil. The outbreaks occurred in July and August 2011 when young and adult goats received a mineral mixture after approximately three days of restriction from the supplement. The animals were kept in barns with a high stocking density and had an inadequate supply of water. In the second outbreak, the goats were supplemented too with brewery residue added to 3.3% of the mixture mineral. From a flock of 191 goats, 12 animals (nine crossbreeds, two Anglo-Nubians and one Boer) showed nervous symptomatology, and the morbidity rate was 6.28%. The most frequent clinical signs were head lowering, head tilt, muscle weakness, mydriasis and ataxia. Three goats died, four recovered spontaneously from the first outbreak, and five recovered from the second outbreak over three days after treatment with dexamethasone, thiamine and gradual water supply. The lethality rate was 25%. In two animals, necropsy was performed, and no macro- or microscopic alterations in the nervous system or other organs were observed. These negative pathological findings indicate that the neurological clinical signs were initiated by functional disturbances in the central nervous system. In the brain, a high sodium concentration (3703 and 3675 ppm), compared with the reference values for cattle was detected. Normonatremia was observed in the sick goats, and hypernatremia was observed in the goats from the same lot of affected animals based on blood serum samples obtained before the first outbreak. These results pointed out that the goats were consuming high sodium concentrations. Normal values for the sick animals were assigned after rapid osmotic control via adequate water intake. We conclude that the salt poisoning on the goats occurred due to a high intake of the mineral mixture caused by management errors and associated with water restrictions.

Accidental sodium chloride poisoning in sheep – a case study

In April 2015, a farmer in the Silesia Region, Czech Republic, suffered a massive loss of 51 sheep. Two days before the incident, the flock of approximately 300 sheep were transferred from their wintering stable to pastureland. The pasture had a brook as a source of drinking water and in addition, a water cistern with drinking water was provided as well as mineral salt licks; otherwise the animals were left to graze with no supplementary feed. During the night of 28/29 April it rained heavily. The salt blocks were damaged and softened, showing signs of intensive nibbling. In the morning of 29 April, dead animals were found all over the pastureland. Four of the sheep were sent for post mortem examination and toxicological analyses. Evidence of extremely high concentrations of NaCl in the liver samples and characteristic pathologicalanatomical findings confirmed the suspicion that the sheep had died of fodder salt poisoning. The rapid and extreme change in the weather conditions, soaking of the otherwise solid salt lick, and the short period of acclimatisation of the sheep to the pasture were at fault. The main preventative measure is to respect the transitory period for the animals to get accustomed to a different kind of roughage and local conditions. This case is noteworthy because of the number of animals affected, the speed of the poisoning progress, and the detailed pathological examination of the dead animals. As there is a limited number of articles describing salt poisoning in sheep, this case study may contribute to the broadening of the knowledge on this issue.