Clinical signs and their association with herd demographics and porcine reproductive and respiratory syndrome (PRRS) control strategies in PRRS PCR-positive swine herds in Ontario

The purposes of this study were to describe the clinical signs observed in PRRS positive herds during a porcine reproductive and respiratory syndrome (PRRS) outbreak in Ontario and to determine associations between these clinical signs and herd demographics and PRRS control strategies. All PRRS polymerase chain reaction-(PCR)-positive submissions to a diagnostic laboratory between September 1, 2004 and August 31, 2007 were identified (n = 1864). After meeting eligibility requirements and agreeing to voluntary study participation, producers from 455 of these submissions were surveyed for information on clinical signs observed in their herds, herd demographics, and PRRS control strategies used in their herds at the time that the PCR-positive samples were taken. Larger herd size was associated with an increased risk of reporting abortion, weakborn piglets, off-feed sows, and sow mortality in sow herds, and with an increased risk of reporting mortality in finishing herds. When disease control strategies were examined, use of a commercial PRRS vaccine in sows and gilts was associated with a decreased risk of reporting weakborn pigs and high pre-weaning mortality, while the use of serum inoculation in breeding animals was associated with an increased risk of reporting off-feed sows and sow mortality. Providing biofeedback of stillborn/mummified piglets, placenta or feces to gilts was associated with an increased risk of reporting respiratory disease and mortality in finishing pigs while all-in/all-out flow in farrowing rooms was associated with an increased risk of reporting sow mortality and weakborn piglets.     

Seroprevalence and risk factors associated with Toxoplasma gondii infection in pig farms from Catalonia, north-eastern Spain

Seroprevalence and associated risk factors for Toxoplasma gondii infection in pigs were analyzed in 1202 sera samples, including sows and pigs of three, seven, 11, 15 and 20 weeks of age, from 23 farms in Catalonia, north-eastern Spain. Antibodies were tested by the modified agglutination test (MAT) at titers ?1:25. Antibodies to T. gondii were found in 228 samples (19.0%; 95% CI: 16.8-21.2). The individual prevalence in animals higher than 7 weeks of age was 22.8% (174/762; 95% CI: 16.6-29.0) and the within-farm prevalence ranged from 7.1% to 36.4%. Statistically significant differences were found among age classes. The risk factors significantly associated with T. gondii seroprevalence were the presence of cats, percentage of mortality at weaning and the presence of outdoor facilities in the farms. The seroprevalence observed in the present study indicates widespread exposure to T. gondii among domestic pigs in Catalonia, which may have important implications for public health.     

Pathologic and immunohistochemical findings in an outbreak of systemic toxoplasmosis in a mob of red kangaroos

Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos (Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials.     

Seroprevalence of Toxoplasma gondii infection in Norwegian dairy goats

Background

Toxoplasma gondii is a major problem for the sheep industry as it may cause reproduction problems. The importance of T. gondii in Norwegian goat herds is uncertain, but outbreaks of toxoplasmosis in dairy goat farms have been recorded. The aim of this study was to describe the prevalence of T. gondii infection in Norwegian dairy goats by using serology.

Findings

Goat serum originally collected as part of two nationwide surveillance and control programmes between 2002 and 2008 were examined for T. gondii antibodies by using direct agglutination test. In total, 55 of 73 herds (75%) had one or more serologically positive animals, while 377 of 2188 (17%) of the individual samples tested positive for T. gondii antibodies.

Conclusions

This is the first prevalence study of T. gondii infection in Norwegian goats. The results show that Norwegian goat herds are commonly exposed to T. gondii. Nevertheless, the majority of goat herds have a low prevalence of antibody positive animals, which make them vulnerable to infections with T. gondii during the gestation period.     

Molecular genotyping and serological evaluation of Toxoplasma gondii in mothers and their spontaneous aborted fetuses in Southwest of Iran

BackgroundGiven the lack of routine screening and the high prevalence of toxoplasmosis in pregnant women in Iran, the current study aimed to find out the rate and features of Toxoplasma gondii infection in the spontaneously aborted human fetuses in Kohgiluyeh and Boyer-Ahmad Province, Southwestern Iran.MethodsThis cross-sectional study was performed on 100 spontaneously aborted fetuses’ tissues and their mother blood samples. The mothers’ sera were evaluated for anti-Toxoplasma antibodies while their buffy coat and aborted fetuses tissues were evaluated for Toxoplasma DNA. PCR product at GRA6 locus was sequenced and phylogenetic analysis was done. Likewise, quantitative Real-Time PCR was performed to find out the parasite burdens in mothers buffy coat and fetuses tissues.ResultsUsing serological method, anti-Toxoplasma IgG and IgM antibodies were detected in 7 (7%) and 3 (3%) out of 100 sera from women with spontaneous abortion. Real-time PCR method detected T. gondii DNA in the buffy coat of one seronegative and 2 (out of 3) IgM seropositive cases. None of the samples from aborted fetuses were infected with T. gondii. BLAST and phylogenetic analysis showed that the sequenced isolates belonged to type I of T. gondii and two identified T. gondii isolates were taxonomically grouped into one clade.ConclusionOur findings revealed type I genotype of T. gondii in two mothers with spontaneous abortion, without fetus involvement. It is necessary to examine more aborted fetuses’ samples from different geographical areas to determine the association between Toxoplasma genotype and abortion.     

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ? 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.     

Evidence of Toxoplasma gondii Exposure among Horses in Korea

The present study investigated the seroprevalence of Toxoplasma gondii (T. gondii) antibodies by ELISA in horses reared in Korea. Serum samples were collected from 2009 through 2013 from 816 horses reared in Korea. Analysis was performed using a commercial toxoplasmosis ELISA kit to detect anti-T. gondii antibodies. Overall, 24 out of 816 horses (2.9%) were seropositive for T. gondii. The result was analyzed by age, gender, breed and region. Significant differences were observed according to breed and region (P<0.05). This is the first nationwide serological investigation of T. gondii in horses reared in Korea. The study results reveal that T. gondii occurs nationwide in Korean horses.     

Herd and sow-related risk factors for mortality in sows in group-housed systems

Mortality of sows is a major problem for pig production worldwide. In this study, we used hierarchical multivariable logistic analyses to investigate different risk factors for mortality at the sow and herd level in herds with group-housed pregnant sows. Data included 3652 pregnant and 1266 lactating sows from 34 sow herds. A clinical examination for 16 clinical signs was carried out for each sow, and information about 16 herd related factors was obtained by interviews. Farm records were used to obtain information about whether or not sows died suddenly or were euthanized within 3 months after the clinical examination. Factors increasing the risk of sow mortality in the gestation unit were solid pen floors (OR = 1.87), presence of vulva bites (OR = 1.73) and unwillingness to stand when approached (OR = 1.62). Factors increasing the risk of sow mortality in the lactation unit were pale vulva color (OR = 12.69), body leanness (OR = 4.11), and presence of shoulder ulcers (OR = 2.89). The estimated between herd variation was small. Thus, the findings for the sow level variables may be generally applicable for sows in herds with group housed systems.     

An outbreak of toxoplasmosis in farmed mink (Mustela vison S.).

A large Wisconsin mink (Mustela vison) farm experienced an outbreak of toxoplasmosis in the spring of 1999 following an outbreak of canine distemper during the previous fall. Major clinical signs for pregnant females included reduced feed consumption, abortions, and stillborn kits; kits < or =3 weeks old experienced ataxia and mortality. Of 7,800 females, 1,976 (26%) lost their entire litter either from abortion or neonatal mortality. Kit mortality from 7 days to 3 weeks of age was 3,300, and overall kit mortality attributed to the toxoplasmosis outbreak was 10,408. Six neonatal mink kits, 12 3-week-old kits, and 2 adult female mink were submitted to the University of Minnesota Veterinary Diagnostic Laboratory for diagnostic workup. Gross postmortem lesions were limited to empty stomachs (12 of 12 kits) and pale livers (4 of 12 kits) for the 3-week-old kits. Major microscopic lesions included interstitial pneumonia, encephalitis, encephalomalacia, and myocarditis. Toxoplasmosis was diagnosed by microscopic lesions, microscopic lesion distribution, and the detection of Toxoplasma gondii tachyzoites by immunohistochemistry. This is the first detailed report of an outbreak of toxoplasmosis in mink in the United States.     

Associations between genetics, farm characteristics and clinical disease in field outbreaks of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS) is a disease of domestic swine characterized by exceptionally high clinical variability. This study addresses the question of whether clinical variability in PRRS results from (a) genetic variation among viral isolates and/or (b) variation in management practices among farms on which isolates are found. Genetic data (open reading frame 5 gene sequences) and data on farm characteristics and associated clinical disease signs were collected for 62 PRRS virus (PRRSV) field isolates, representing 52 farms. Clinical disease signs were interrelated — confirming that a true reproductive syndrome exists (involving abortions, infertility in sows, deaths of sows and preweaning mortality).

Pairs of farms experiencing deaths in their sow populations also tended to share viral isolates which were more similar to one another than expected by chance alone. This implies that sow death (one of the more-severe manifestations of PRRS) is under genetic influence. Large herd size was a significant risk factor for the death of sows and for respiratory disease in nursery pigs. All-in–all-out management practices in the nursery were protective against reproductive signs in the sow herd. All-in–all-out management practices in the finishing stages of production were protective against respiratory disease in nursery pigs — but were paradoxically associated with an increased risk of infertility in sows. These results suggest that farm-management practices can also influence which PRRS clinical signs are manifested during an outbreak. In general, signs associated with PRRS appear to result from a combination of genetic factors and herd-management characteristics. The relative contributions of these two influences differ depending on the specific clinical sign in question.     

Influence of farm application of oregano on performances of sows

This study was performed in a large commercial herd in eastern Europe to test the effect of oregano feed supplementation. Sows were studied in a unit where alternate farrowing groups were given diets containing 1000 ppm oregano in the prefarrowing and lactation diet. Oregano-treated groups showed a lower (P = 0.003) annual sow mortality rate, a lower (P = 0.03) sow culling rate during lactation, an increased (P = 0.01) subsequent farrowing rate, and more (P = 0.05) live-born piglets per litter compared with the nontreated sows. The conclusion was that dietary oregano supplementation improved the reproductive performance of sows in this herd.     

Risk factors for high sow mortality in French swine herds

Episodes of high sow mortality rates affect profitability of swine farms. However, relevant control actions are difficult to implement. The objective of this study was to identify the risk factors for high levels of sow mortality rate (HM) in French swine herds. A case-control study was carried out in 102 swine herds located in Brittany (western France). Level of sow mortality of a herd was quantified by the annual mortality rate using sow-days as denominator. Fifty-five (53.9%) herds which experienced a sow mortality rate over 5% were classified as HM herds. Logistic regression was used to assess associations of managerial practices and disease prevalence with the odds of HM. High prevalence of urinary tract infections, metritis or lameness were significantly associated with a HM herd status (P < 0.10, OR ranging from 3.4 to 5.2). Multiplying herds were herds at higher risk for sow mortality than commercial farrow-to-finish herds. Providing three meals per day instead of two to dry sows decreased the odds of HM. Feeding plans where the maximum daily amount of feed provided to lactating sows was lower than 8 kg and was reached before 15 d in lactation were related to lower odds of HM (P < 0.10). Average age at weaning of 28 d or more and/or small average litter size at birth (12 piglets or less) were associated with higher odds of experiencing HM.     

Feline immunodeficiency virus, feline leukemia virus and Toxoplasma gondii in stray and household cats in Kerman-Iran: Seroprevalence and correlation with clinical and laboratory findings

This study was carried out to determine the seroprevalence of feline leukemia virus (FeLV), feline immunodeficiency virus (FIV) and Toxoplasma gondii (T. gondii) infection among stray and owned cats in southeastern Iran and to identify the influence of age, sex, lifestyle, health status, and laboratory findings on seropositivity. The overall infection rate for FIV, FeLV, and T. gondii was 19.2%, 14.2%, and 32.1% respectively. Results of the multivariate logistic regression analysis showed that old adults more likely to be seropositive than juveniles for FIV, FeLV, and T. gondii (adjusted odds ratios [ORs], 1.84, 1.56, and 2.57 respectively). Anemic and diseased cats ([ORs], 6.62 and 0.9) were at a greater risk of testing positive for FeLV. Male cats were 4.91 times as likely to have FIV as were female and hyperglobulinemia was significantly more prevalent in FIV-infected cats ([ORs], 3.4). In conclusion, FIV and FeLV seem to be endemic in Iran and retroviral-associated immunosuppression may be a risk factor for active toxoplasmosis in infected cats.     

Prevalence of infection with porcine circovirus-2 (PCV-2) and porcine reproductive and respiratory syndrome virus (PRRSV) in an integrated swine production system experiencing postweaning multisystemic wasting syndrome

The objective of this study was to evaluate the prevalence of infection with porcine circovirus-2 (PCV-2) and porcine reproductive and respiratory syndrome virus (PRRSV) through a longitudinal study in an integrated swine production system (7 farms) experiencing postweaning multisystemic wasting syndrome (PMWS). Risk factors for PCV-2 infection and for PCV-2 and PRRSV coinfection were also evaluated. Fifteen sows from each herd and 4 non-cross-fostered piglets from each sow were randomly selected at farrowing and ear-tagged at birth. Serum samples were analyzed for antibodies to PCV-2 and for detection of the PCV-2 and PRRSV genomes. Statistical analyses involved 2 approaches. The 1st approach characterized the dynamics of PCV-2 infection and their relationship with PRRSV infection. The 2nd approach analyzed the probability of being infected by PCV-2 or by both PCV-2 and PRRSV through a generalized linear mixed model incorporating sow and farm characteristics. At the 1st sampling time (1 wk of age), there was a significant relationship between sow PCV-2 infection and piglet PCV-2 infection (P < 0.0001). The risk of PCV-2 and PRRSV coinfection was 1.85 times greater in piglets from a sow with low titers of PCV-2 antibodies than in piglets from sows with medium to high titers (P = 0.03) and was 2.54, 2.40, and 2.02 times greater, respectively, in piglets from primiparous sows, PCV-2-infected sows, and farms in an area of high pig density than in piglets from sows of higher parity (P = 0.004), noninfected sows (P = 0.04), and farms in a low-density area (P = 0.09).     

Herd specific risk factors for Mycoplasma hyopneumoniae infections in suckling pigs at the age of weaning

Background

Mycoplasma hyopneumoniae is the etiologic agent of enzootic pneumonia mainly occurring in fattening pigs. It is assumed that horizontal transmission of the pathogen during nursery and growing phase starts with few suckling pigs vertically infected by the sow. The aim of the present study was the exploration of the herd prevalence of M. hyopneumoniae infections in suckling pigs followed by an investigation of various herd specific factors for their potential of influencing the occurrence of this pathogen at the age of weaning.

Results

In this cross-sectional study, 125 breeding herds were examined by taking nasal swabs from 20 suckling pigs in each herd. In total, 3.9% (98/2500) of all nasal swabs were tested positive for M. hyopneumoniae by real-time PCR. Piglets tested positive originated from 46 different herds resulting in an overall herd prevalence of 36.8% (46/125) for M. hyopneumoniae infection in pigs at the age of weaning. While the herds were epidemiologically characterized, the risk for demonstration of M. hyopneumoniae was significantly increased, when the number of purchased gilts per year was more than 120 (OR: 5.8), and when the number of farrowing pens per compartment was higher than 16 (OR: 3.3). In herds with a planned and segregated production, where groups of sows entered previously emptied farrowing units, the risk for demonstration of M. hyopneumoniae in piglets was higher in herds with two or four weeks between batches than in herds with one or three weeks between batches (OR: 2.7).

Conclusions

In this cross-sectional study, several risk factors could be identified enhancing the probability of breeding herds to raise suckling pigs already infected with M. hyopneumoniae at the time of weaning. Interestingly, some factors (farrowing rhythm, gilt acclimatisation issues) were overlapping with those also influencing the seroprevalences among sows or the transmission of the pathogen between older age groups. Taking the multifactorial character of enzootic pneumonia into account, the results of this study substantiate that a comprehensive herd specific prevention programme is a prerequisite to reduce transmission of and disease caused by M. hyopneumoniae.     

Case Study: Chronic Erysipelas of the Sow – a Subclinical Manifestation of Reproductive Problems

Systemic infections with Erysipelothrix rhusiopathiae are usually associated with skin lesions, vegetative endocarditis and arthritis, but they can also cause reproductive symptoms such as abortion, increased stillbirths, and smaller litter size. In a large Hungarian breeding unit that had ceased to vaccinate the sows against erysipelas, an increased incidence of pre- and post-partal vulval discharge, increased weaning-to-oestrus intervals, decreased farrowing rates, and reductions in total number of pigets born and live-born litter size were reported. Anterior vaginal swabs were obtained from 64 sows shortly before parturition and they all yielded heavy growths of E. rhusiopathiae . A vaccination programme with a killed vaccine was reinstated and subsequently the incidence of vulval discharge and weaning-to-oestrus intervals were decreased and total born and live-born litter size were increased. In the absence of a control group definitive conclusions can not be made regarding the effect of vaccination against E. rhusiopathiae on sow fertility. However, it is not unreasonable to suggest that the aetiology of the reduced sow fertility in the present herd did involve E. rhusiopathiae and that appropriate vaccinations subsequently protected the sows from the disease.     

Pathologic consequences of a severe influenza outbreak (swine virus A/H1N1) under natural conditions in the non-immune sow at the beginning of pregnancy

Pathological consequences of a severe outbreak of swine influenza (H1N1 virus) in the non immune sow at the beginning of pregnancy, under natural conditions. A sudden acute outbreak of fever, depression, anorexia and coughing in a group of nulliparous sows from a herd that was currently under epidemiological investigation lead to build a particular disposal of observation. The clinical signs were daily recorded including rectal temperature. Blood was taken from the sows at the beginning of the troubles and 3 weeks later for the detection of Aujesky's disease, coronavirus TGE-like, Influenza viruses A/H1N1 and A/H3N2 and Mycoplasma hyopneumoniae. Viral detection was attempted from nasal swabs and aborted fetuses during the acute phase. The clinical study showed fever reaching near 41 degrees C on most of the pigs and lasting usually from 2 to 5 days. The diagnosis of Influenza (virus swine H1N1) was established both on serology (massive seroconversion) and on the detection of the virus from the nasal swabs and from an aborted fetus. The control of the lungs of sows "not in pig" and culled showed extended lesions of bronchopneumonia and Pasteurella multocida was found. The technical consequences of this severe outbreak of Influenza on reproduction were mainly important at the beginning of pregnancy. Over 13 sows inseminated less than 1 week before the outbreak, only 3 farrowed (respectively 5.5 and 12 piglets); 7 returned to oestrus and 3 "not a pig" at 21 days (echotomography) did not show signs of heat and were culled. Over 8 pregnant sows (1 month of pregnancy), 6 farrowed normal litters and total embryonic resorption occurred in 2 sows. Over 18 pregnant sows (more than 45 days gestation) one aborted.     

Actinobacillus suis septicemia in mature swine: two outbreaks resembling erysipelas

In the winter of 1987/88 a previously unrecognized septicemic disease syndrome — actinobacillosis in mature sows and gilts — was diagnosed in two minimal-disease swine herds in southwestern Ontario. In herd 1, 34 sows, 2 boars, 13 feeder pigs, and 30 suckling pigs were affected; 11 sows, 2 feeders, and 18 suckling pigs died. In herd 2, 13 sows and 1 feeder pig were affected; 1 sow and 1 feeder pig died. The disease was manifested by moderate fever (39-40.5°C), round or rhomboid erythematous skin lesions, and inappetence. Sudden deaths without previous clinical signs were frequent. Histologically, coccobacillary thromboemboli in superficial and deep dermal vessels were associated with infarcted dermal and epidermal tissues. The causative organism, Actinobacillus suis, was isolated from the affected pigs. Treatment with commonly used antibacterial drugs was effective.

In many respects, the disease resembled acute swine erysipelas and presented diagnostic problems for this reason.

     

Effects of synbiotic-based Bifidobacterium animalis in female rats experimentally infected with Toxoplasma gondii

The aim of this study was to assess the effects of a synbiotic composed of Bifidobacterium animalis and fructooligosaccharides on female rats infected with Toxoplasma gondii. Female Wistar rats, treated or not with dexamethasone, were daily supplemented with synbiotics for 21 days. After 15 days of supplementation, the rats were orally infected with 10⁴T. gondii bradyzoites. Blood samples were collected to measure the levels of IFN-γ, IL-10 and T. gondii antibodies. All synbiotic-supplemented rats survived until the end of the experiment; however, non-supplemented dexamethasone-treated rats died between the fifth and the eighth days after T. gondii infection. Dexamethasone-treated rats supplemented with synbiotics (P < 0.05) were capable of synthesizing IFN-γ, and this immunological response was essential to ensure their survival. In addition, brain cysts were found in one rat not supplemented with synbiotics. Results suggest that the synbiotic composed of B. animalis and fructooligosaccharides may be beneficial to toxoplasmosis control.     

An outbreak of fatal hemorrhagic pneumonia caused by Streptococcus equi subsp. zooepidemicus in shelter dogs

An outbreak of fatal hemorrhagic pneumonia with 70~90% morbidity and 50% mortality occurred in an animal shelter in Yangju, Gyeonggi Province, Korea. Clinically, the affected dogs showed severe respiratory distress within 48 h after arriving in the shelter. The dead were found mainly with nasal bleeding and hematemesis. At necropsy, hemothorax and hemorrhagic pneumonia along with severe pulmonary consolidation was observed, though histopathological analysis showed mainly hemorrhagic bronchopneumonia. Lymphoid depletion was inconsistently seen in the spleen, tonsil and bronchial lymph node. Gram-positive colonies were shown in blood vessels or parenchyma of cerebrum, lung, liver, spleen, and kidney. Also, Streptococcus (S.) equi subsp. zooepidemicus was isolated from the various organs in which the bacterium was microscopically and histologically detected. In addition, approximately 0.9 Kb specific amplicon, antiphagocytic factor H binding protein, was amplified in the bacterial isolates. In this study, we reported an outbreak of canine hemorrhagic bronchopneumonia caused by S. equi subsp. zooepidemicus in an animal shelter in Yangju, Korea.