Från Hernquist till nutid: Hur vår förståelse för häststryparsjukan kvarka har utvecklats

Kvarka är en smittsam hästsjukdom, beskriven redan 1251 av Jordanus Ruffus (33), men finns omnämnd tidigare hos till exempel Pelagonius Saloninus (9). Idag vet vi att kvarka orsakas av bakterien Streptococcus equi subspecies equi (S equi). Hästarna drabbas av en svårartad och smärtfylld luftvägsinfektion. Ofta ses variga bölder i lymfknutorna i huvud och hals. Symtomen kan också vara lindriga och likna en vanlig förkylning. I dag finns vaccin mot kvarka. I den engelskspråkiga litteraturen finns intressanta historiska teckningar av kvarka (25), men där saknas svenskspråkiga källor. I det följande vill vi ge ett svenskt, etymologiskt och historiskt perspektiv på sjukdomen kvarka med avstamp i tiden för den svenska veterinärmedicinens fader, Peter Hernquist, genom några andra svenska företrädare och fram till dagens molekylärbaserade tekniker och möjligheter. Denna resa från historiska metoder till dagens vetenskapliga tillvägagångssätt visar på stora framsteg inom veterinärmedicinen när det gäller förståelsen och hanteringen av kvarka

Spatial and temporal distribution of incidence of acquired equine polyneuropathy in Norway and Sweden, 1995-2012

BACKGROUND: Acquired equine polyneuropathy (AEP) is an emerging disease in horses in Sweden, Norway and Finland since 1995. Affected horses show bilateral pelvic limb knuckling and weakness, sometimes progressing to recumbency and euthanasia. The aetiology is unknown but is thought to be non-infectious and non-genetic, though possibly toxic or toxico-infectious. The objectives of this study were to describe the spatial, temporal and spatio-temporal features of AEP in Norway and Sweden for the period of 1995 to 2012. Data from all documented case farms (n = 136) were used. Space-time interaction clustering of case farms was investigated with a retrospective space-time scan statistic with a space-time permutation model, the space-time K-function and the Jacquez k nearest neighbour (kNN) test. RESULTS: There was a clear seasonality in disease occurrence, as 123 case farms presented their first case from January to May. However, there was large variation in the number of case farms between years. Case farms were more numerous in certain regions. Despite the larger horse population in Sweden, 120 of the case farms were in Norway. Space-time clustering was supported by the K-function and partly by the space-time scan, but not by the Jacquez k nearest neighbour (kNN) test. CONCLUSIONS: The results suggest an aetiology for AEP where the exposure is not consistent in time, but varies during and between years, assuming that the incubation period does not vary greatly. The results further suggest that the exposure varies between regions as well. Two out of three different analytical methods supported spatio-temporal clustering of case farms, which rendered inconclusive results. The negative result in the kNN test might be explained by lack of power, which is due to the small number of outbreaks in relation to the size of the study area and length of the study period, and further by the low to moderate power of methods to detect space-time clustering when the background population is unknown. Further research is needed to study how management, meteorological variables and other factors with local or regional differences may explain outbreaks of AEP

Epidemiological Aspects of Equid Herpesvirus-Associated Myeloencephalopathy (EHM) Outbreaks

: Equid Herpesvirus Myeloencephalopathy (EHM) is a multifactorial disease following an EHV-1 infection in Equidae. We investigated a total of 589 horses on 13 premises in Europe in search of risk factors for the development of EHM. We found that fever (p \u3c 0.001), increasing age (p = 0.032), and female sex (p = 0.042) were risk factors for EHM in a logistic mixed model. Some breeds had a decreased risk to develop EHM compared to others (Shetland and Welsh ponies; p = 0.017; p = 0.031), and fewer EHV-1-vaccinated horses were affected by EHM compared to unvaccinated horses (p = 0.02). Data evaluation was complex due to high variability between outbreaks with regards to construction and environment; viral characteristics and the virus’s transmissibility were affected by operational management. This study confirms earlier suspected host-specific risk factors, and our data support the benefit of high vaccine coverage at high-traffic boarding facilities

Opsonisation and neutrophil phagocytosis in foals and adult horses

Infectious diseases are the main cause of disease and deaths in foals. The neutrophil phagocyte is a part of the early, non-specific immune response, which is essential in defending the host against microbial invasion. Coating of microbes with opsonic factors such as antibodies and complement from serum is required for optimal phagocytosis.Flow cytometric methods were developed and used for studies of equine neutrophil phagocytosis and serum opsonisation of Saccharomyces cerevisiae, Escherichia coli and Actinobacillus equuli, and of the expression of complement receptor subunit CD18 on neutrophils. Foals from birth to 2 months of age and adult horses were studied.Incubation for 15 min was found sufficient for both opsonisation and phagocytosis. Opsonisation of yeast and A. equuli, but not of E. coli, was observed already at low serum concentrations (Complement activation was needed for optimal phagocytosis of all the microbes studied. The classical pathway was required for yeast phagocytosis at low serum concentrations (1.5%) and is the main pathway for C3 deposition with In newborn foals, colostrum ingestion was required to achieve a serum opsonic capacity for all the microbes studied. Serum from foals up to 3-4 weeks of age showed a lower capacity to opsonise yeast, but a higher capacity to opsonise E. coli compared to serum from older foals and horses. No age-related differences were observed in serum opsonisation ofA. equuli. Very low serum concentrations of IgG or IgGb were associated with decreased phagocytosis of yeast and E. coli, but not of A. equuli. However, there were large individual variations in the opsonisation of yeast, irrespective of the concentrations of IgG, by sera from newborn foals and plasma from individual adult donors. This may have been due to different levels of complement activation. Plasma transfusion to healthy 7-day old foals resulted in an increased serum capacity for yeast opsonisation at 14 days.The neutrophil phagocytosis capacity per se was similar in foals and adult horses, and the expression of complementreceptor CD18 was also similar, or higher in the foals.These results emphasise the importance of both antibodies and complement factors in serum for an effective defence against microorganisms in young foals. Intravenous administration of plasma to foals seems to be of some benefit, but additional studies are warranted to characterise the factors involved. Important differences were observed between various microbes in the particular requirements for effective phagocytosis.The involvement of complement in common equine pathological conditions deserves further attention. A better understanding of the equine complement system may lead to improved prophylactic and therapeutic regimens in foals and adult horses