Cross-sectional study of 13 Leptospira serovars in cows in a Colombian dairy region / Estudio transversal de 13 serovares de Leptospira en vacas en una región lechera colombiana / Estudo transversal de 13 sorotipos de Leptospira em vacas em uma região leitera colombiana

Abstract Background: Leptospirosis in cattle is recognized as a major cause of reproductive loses due to abortions, early embryonic death, and infertility. The type of Leptospira serovars that are currently circulating in Colombian herds is largely unknown due to the lack of national reports. Objective: The prevalence of antibodies specific to 13 Leptospira spp serovars was investigated in unvaccinated cows from 26 herds in San Pedro de los Milagros (Province of Antioquia) dairy region. Methods: Microscopic agglutination test was used on serum samples, following WHO recommendations. Results: A total of 112/900 (12.4%) of the animals had antibody titers of 1:100 or greater to at least one Leptospira serovar. Of those positive, 34/900 (3,8%) animals seroconverted to two or more serovars. In order of decreasing prevalence, the serovars detected were: hardjo prajitno, pomona, grippotyphosa, tarassovi, copenhageni, canicola, cellodeni and bratislava. There were 28 animals seropositive to serovar hardjo. Conclusion: Our results indicate that leptospirosis should be included as a differential diagnosis for various reproductive problems in this region.

Resumen Antecedentes: La leptospirosis es la mayor causal de pérdidas reproductivas debidas a abortos, muerte embrionaria temprana e infertilidad. Se desconocen los serovares de Leptospira que actualmente se encuentran circulando en el rebaño colombiano debido a la falta de reportes nacionales. Objetivo: Se investigó la prevalencia de anticuerpos específicos para 13 serovares de Leptospira spp en vacas no vacunadas de 26 rebaños en la región lechera de San Pedro de los Milagros (Provincia de Antioquia). Métodos: La prueba de aglutinación microscópica fue empleada en muestras de suero de acuerdo a las recomendaciones de la OMS. Resultados: Un total de 112/900 (12,4%) de los animales presentaron títulos de anticuerpos de 1:100 o superiores para al menos un serovar de Leptospira. Entre los positivos, el 34/900 (3,8%) de los animales presentaron seroconversión para dos o más serovares. En orden decreciente de prevalencia, los serovares detectados fueron: hardjo prajitno, pomona, grippotyphosa, tarassovi, copenhageni, canicola, cellodeni y Bratislava. En total, 28 animales fueron seropositivos al serovar hardjo. Conclusión: La leptospirosis debería ser incluida como diagnóstico diferencial en problemas reproductivos en esta región.

Resumo Antecedentes: Aleptospirose em bovinos é reconhecida como uma das principais causas de perdas reprodutivas devido a abortos, morte embrionária precoce e infertidade. Os sorotipos de Leptospira que estão atualmente em circulação no rebanho colombiano não se conhecem devido à falta de reportes nacionais. Objetivo: Neste estúdio foi investigada a prevalência de anticorpos específicos para 13 sorovares de Leptospira spp em vacas não vacinadas de 26 rebanhos leiteiros da região de San Pedro, Antioquia. Métodos: Foi empregado o teste de aglutinação microscópica (MAT) em amostras de soro de acordo com as recomendações da OMS. Resultados: Um total de 112/900 (12,4%) animais apresentaram títulos de anticorpos de 1:100 ou superiores para pelo menos um sorotipo de Leptospira. Dos animais positivos, 34/900 (3,8%) soroconverteram para dois ou mais sorotipos. A fim de diminuir a prevalência, foram detectados os sorotipos: hardjo, prajitno, pomona, grippotyphosa, tarassovi, copenhageni, canicola, cellodeni e Bratislava. Um total de28 animais foram soropositivos para o sorotipo hardjo. Conclusão: Os resultados indicam que a leptospirose deveria ser incluída nos diagnósticos diferenciais para o diagnóstico diferencial de problemas em doenças reprodutivas nos bovinos de Antioquia.

Survey of gastrointestinal parasites, liver flukes and lungworm in feces from dairy cattle in the high tropics of Antioquia, Colombia.

A cross sectional study was undertaken to determine the prevalence and intensity of parasitic infections in dairy cattle in the high tropics of Colombia. A total of 1003 rectal samples were collected from dairy cows at 29 farms between May and June 2014 to represent the number of farms, age groups, and size of the 65,000-cow population in the municipality of San Pedro de los Milagros. Coprological techniques were used to detect gastrointestinal nematodes, liver flukes, coccidian oocysts, and first larval stage counts of Dictyocaulus viviparus. In order of decreasing prevalence, the following parasites were detected: coccidial oocyst (36.7%; 95% CIs, 31.6-42.7), strongyle nematodes (31.6%, 27.8-35.4), liver flukes (30.9%, 21.5-37.5), cestodes (8.4%, 7.1-9.7), and D. viviparus (5.4%, 3.4-7.5). Co-infections by all possible combinations of the three most predominant groups occurred in 11 to 15% of the animals. There were significant differences in infection rates between age groups, with higher risk of liver fluke infection in animals older than 1 year of age (odds ratio (OR) = 3.2), but lower presence for coccidia and strongyles (OR = 0.19 and 0.51, respectively). For Fasciola hepatica, within-herd prevalences of > 25% in 16 farms and 94 of 281 (33.5%) animals with > 5 eggs per gram (epg) indicate that significant production losses are likely occurring. The variation in the prevalence of gastrointestinal parasites and liver flukes, together with the level of infection among age groups, could be used in integrated management programs to establish selective anthelmintic treatments and select for heritable traits of host resistance. These results serve as a baseline for future studies to determine the success of control measures and should increase awareness that subclinical parasitism is widespread in the livestock sector.

Association of BoLA-DRB3 and TLR4 alleles with subclinical mastitis in cattle from Colombia / Asociación de los alelos BoLA-DRB3 y TLR4 con mastitis subclínica en vacas de Colombia / Associação de Bola-DRB3 alelos e TLR4 com mastite subclínica em vacas da Colômbia

Background: molecular markers for genetic resistance can be used to control mastitis in dairy cattle. The Major Histocompatibility Complex and the Toll-like receptor 4 (TLR4) are two promising genes that warrant investigation. Objective: to identify associations between genotypes of BoLA-DRB3 locus and T4CRBR2 fragment and subclinical mastitis (SM). Methods: 996 lactating cows from 32 herds comprising Holstein (80%), Holstein x Jersey cross (12.5%), and other crosses (7.5%) were evaluated monthly during two years, diagnosed for SM and genotyped for the second exon of BoLA DRB3 and the TLR4 coreceptor-binding region 2 (T4CRBR2) using a Polymerase chain reaction-restriction fragment length polymorphism technique (PCRRFLP). The association between candidate alleles and subclinical mastitis was measured by logistic regression. Results: the most frequently observed alleles for BoLA-DRB3 were DRB3.2 *8, *22, *24, *16, *10, *23, *gba, *11, *2, *mbb, *jba, *3, and *15, accounting for 58.9% of the population. Frequencies for T4CRBR2 alleles A and B were 0.352 and 0.647, respectively. Based on 57,408 observations during the period, the mean SM prevalence was 16.2% (95% CI 13.0 and 19.4) per udder quarter and 37.6% (95% CI 32.1 and 43.2) per cow. The predominant microorganisms isolated from SM quarters were Streptococcus agalactiae and Coagulase-Negative Staphylococci (CNS). Allele DRB3.2 *23 was associated with SM occurrence and CNS infection. No alleles were associated with Streptococcus agalactiae infection. Allele *mbb was associated with occurrence of CNS infection and alleles *jba and *15 were associated with resistance to CNS infection. No significant relationship between T4CRBR2 and SM was observed. Conclusion: DRB3.2 gen may play an important role in the occurrence of SM and certain alleles may confer resistance to specific pathogens.

Antecedentes: los marcadores moleculares genéticos de resistencia para mastitis bovina son una herramienta para el control de la enfermedad en rebaños lecheros. Los genes del Complejo Mayor de Histocompatibilidad y el Receptor tipo Toll 4 (TLR4) son dos genes candidatos promisorios que justifica investigar. Objetivo: identificar asociaciones entre los genotipos del locus BoLA-DRB3 y del fragmento T4CRBR2 con la ocurrencia de mastitis subclínica. Métodos: 996 vacas lactantes de 32 hatos de las razas Holstein (80%), Holstein x Jersey (12,5%) y otros cruces (7,5%), fueron visitadas mensualmente por dos años, diagnosticadas para mastitis subclínica y genotipificadas para el segundo exón del DRB3 y para la región 2 de unión al correceptor del TLR4 (T4CRBR2) por medio de las técnicas de Reacción en cadena de la polimerasa y de Longitud del polimorfismo del fragmento de restricción (PCR-RFLP). La asociación entre los alelos candidatos y la mastitis subclínica se midió por regresión logística. Resultados: los alelos más frecuentes para el DRB3.2 fueron *8, *22, *24, *16, *10, *23, *gba, *11, *2, *mbb, *jba, *3 y *15, que suman el 58,9% del total en la población. Las frecuencias para los alelos A y B del T4CRBR2 fueron de 0,352 y 0,647, respectivamente. Basados en 57.408 observaciones, la prevalencia de MS a nivel de cuarto fue 16,2% (95% IC 13,0 y 19,4) y a nivel de vaca fue de 37,6% (95% IC 32,1 y 43,2). Los microorganismos más frecuentes fueron Streptococcus agalactiae y Estafilococo Coagulasa Negativo (ECN). El alelo DRB3.2 *23 fue el más asociado con la ocurrencia de MS y con la infección por ECN. No se hallaron alelos asociados a infección con mastitis por Streptococcus agalactiae. Con respecto a la infección por ECN, el *mbb se asoció con la ocurrencia y los alelos *jba y *15 se asociaron con resistencia. No se observó asociación entre T4CRBR2 y MS. Conclusión: el gen DRB3.2 puede jugar un papel importante en la presencia de MS y ciertos alelos pueden conferir resistencia a patógenos específicos.

Antecedentes: o uso de marcadores moleculares de resistência para mastites permite controlar esta doença em rebanhos leiteiros. Os genes Toll Like Receptor 4 (TLR4) e o Complexo Mayor de Histocompatibilidade são dois genes candidatos promissórios que justifica pesquisar. Objetivo: identificar associações entre genótipos do locus BoLA-DRB3 e do fragmento T4CRBR2 com a ocorrência de mastite subclínica. Método: 996 vacas em lactação de 32 rebanhos da raça Holandesa (80%), Holandesa x Jersey (12,5%) e outras cruzas (7,5%) foram visitadas mensalmente por dois anos, diagnosticadas para mastites subclínica e genotipadas para o exon segunda BoLA DRB3 e região 2 da ligação co-receptor TLR4 (T4CRBR2) através das técnicas de Reação em Cadeia da Polimerase e do Polimorfismo de Comprimento do Fragmento de Restrição (PCRRFLP). A associação entre alelos candidatos e mastite subclínica foi realizada por meio de regressão logística. Resultados: os alelos mais frequentes *8, *22, *24, *16, *10, *23, *gba, *11, *2, *mbb, *jba, *3 e *15, com um 58,9% do total da população. As frequências dos alelos A e B do T4CRBR2 foram 0,352 e 0,647, respectivamente. Com base em 57.408 observações, a prevalência da SM em quartos mamários foi de 16,2% ((IC 95% 13,0 e 19,4) e ao nível de vaca foi de 37,6% (IC 95% 32,1 e 43,2). Os microrganismos mais comuns foram: Streptococcus agalactiae e Estafilococos Coagulase-negativo, ECN. O alelo DRB3.2 *23 foi o mais associado com a ocorrência de SM e com a infecção por ECN. Não foram encontrados alelos associados à infecção por Streptococcus agalactiae. Em relação à infecção por ECN, o *mbb esteve associado com ocorrência e os alelos *jba e *15 estiveram associados com resistência. Não existiu associação entre MS e os alelos do T4CRBR2. Conclusão: o gene DRB3.2 bovino pode desempenhar um papel importante na presencia de MS e alguns alelos podem conferir resistência à patógenos específicos.

Prevalence of mastitis in dairy herds in Eastern Antioquia / Prevalencia de mastitis en siete hatos lecheros del oriente antioqueño / Prevalência da mastite em sete rebanhos leiteiros na região leste da Antioquia

Seven dairy cattle farms from eastern Antioquia were tested for mastitis in a cross-sectional study with a non-probabilistic convenience sampling procedure. Each udder quarter of 290 lactating cows was evaluated through the California Mastitis Test in order to determine the prevalence of subclinical mastitis. Milk from positive quarters underwent somatic cell count (SCC), cell culture and antibiotic sensitivity tests. The prevalence of subclinical mastitis per quarter was 19.9% (228 quarters). Only 11 quarters (0.95%) had clinical mastitis. The average SCC for all quarters was 1,105,733 cells/mL. Streptococcus dysgalactiae was the most common bacteria observed (29.5%) in the 226 cultures evaluated, followed by coagulasenegative staphylococci (CNS, 23%), and Staphylococcus aureus (10.3%). The frequency of contagiouspathogens and environmental pathogens was 37.8% and 49.3%, respectively. This study confirms that mastitis remains elevated in this region, suggesting a continuous lack of milking hygiene and education of farm personnel.

Se realizó un estudio descriptivo de corte, y se hizo un muestreo no probabilístico de conveniencia, en siete fincas de ganado de leche localizadas en el oriente antioqueño. Se evaluó cada cuarto de 290 vacas en producción láctea mediante la realización del California Mastitis Test (CMT) con el fin de determinar la prevalencia de mastitis por cuarto y por vaca. A la leche proveniente de los cuartos positivos mayores a trazas, se les realizó recuento de células somáticas (RCS), cultivo y antibiograma. La prevalencia de mastitis subclínica por cuarto fue de 19.9% (228 cuartos) y 11 cuartos (0.95%) presentaron mastitis clínica. El promedio del RCS para todos los cuartos fue de 1.105.733 céls/ml. En los 226 cultivos, Streptococcus dysgalactiae fue la bacteria más común (29.5%), le siguieron estafilococos coagulasa negativo (ECN) (23%) y Staphylococcus aureus (10.3%). La frecuencia de patógenos contagiosos fue 37.8%, entre tanto que la de ambientales fue 49.3%.

Foi realizado um estudo de corte, e se realizou uma amostragem não probabilística em sete fazendas de gado leiteiro localizado no leste da Antioquia. Foram avaliados trimestralmente 290 vacas em produção de leite mediante a implementação do California Mastitis Test (CMT) para determinar a prevalência de mastite subclínica em cada quarto da vaca. Nos quartos positivos foi realizada a contagem de células somáticas (CCS) no leite, o cultivo microbiológico e análises de sensibilidade. A prevalência de mastite subclínica por quarto foi de 19.9% (228 quartos) e 11 (0.95%) apresentaram mastite clínica. A CCS média para todas os quartos foi 1.105.733 células / ml. Em 226 cultivos, o Streptococcus dysgalactiae foi a bacteria mais comum (29.5%), seguido por estafilococus coagulase negativo (ECN) (23%) e Staphylococcus aureus (10.3%). A reqüência de agentes patogénicos contagiosos foi de 37.8% e patógenos ambientais foi de 49.3%.

Seroprevalencia e incidencia de Brucella sp envacunadores del Programa para el control de brucelosisbovina, en el Departamento de Antioquia-Colombia / Seroprevalência e incidência de Brucella sp em vacinadores do Programa para ocontrole de bruceloses bovina, no Departamento da Antioquia-Colômbia / Seroprevalence and incidence of Brucella sp among workers of the brucelosis control program in department of Antioquia, Colombia

La brucelosis es un problema de salud pública en el ámbito ocupacional de trabajadores rurales yejecutores de los programas de vacunación de la enfermedad en el ganado. La exploración de la positividady de los factores asociados es necesaria para establecer medidas preventivas en esta población trabajadora.El objetivo de este estudio fue determinar la seroprevalencia e incidencia de Brucelosis en vacunadoresdel programa para el control de Brucelosis bovina en el Departamento de Antioquia- Colombia. Se realizóun estudio de cohorte concurrente en vacunadores del programa para el control de brucelosis bovina,a quienes se les hizo seguimiento antes y después del ciclo de vacunación con el fin de determinar laseropositividad para brucelosis. Se estimó la positividad con dos pruebas inmunológicas diferentes: Rosade Bengala y Elisa Competitivo. Para el primer muestreo de 251 personas, de quienes el 10.8% (IC95%6.4 %-14.3%) fueron positivos a Rosa de Bengala. En el segundo muestreo participaron 220 personas,de quienes el 15.4% (IC95%10.4 % -20.4%) resultaron positivas. Se observó una seroconversión del 5.75%(IC95% 2.0-9.5) para Rosa de Bengala. La positividad general encontrada por Elisa Competitivo para elprimer muestreo fue del 25% (IC 95% 8.65 – 49.10), y para el segundo muestreo del 34.3% (IC95% 17.13 –51.4). Se observó una seroconversión del 5.75% (IC 95% 2.002-9.493) para Rosa de Bengala y del 38.5% (IC 95% 13.858-68.422). No se encontraron diferencias entre las proporciones de positividad entre losmuestreos, sin embargo la seroconversión individual es un aspecto que puede alterar esta diferencia si serealiza un seguimiento más prolongado de cada una de las variables.

Brucellosis is a public health problem in the occupational context of abattoir workers and cattlevaccinators. The exploration of positives and its associated factors is necessary to the establishmentof preventive measures on this population. The objective of the present study was to determine theseroprevalence and incidence of Brucellosis in workers of the Brucellosis control program in Antioquia– Colombia. It took place a cohort study in two different moments, before the cycle and after the cycle.For the first moment there were 251 individuals and for the second 221. Every individual was exploredby a complete questionnaire. In the other hand all workers were subject to vennopunction and bloodextraction, for serology examination with Rose Bengal test and Competitive ELISA. They wereexaminated sociodemographic, occupational and clinical variables in all the participants of the study.The seroprevalence of Rose Bengal test (RBT) for the first moment of the study was 10.8 (IC 95% 6.39-14.32) in the second moment the seroprevalence was 15.4% (IC 95% 10.40 -20.36) with the same test. Theseroconvertion was 5.7% (IC 95% 2.002-9.493) para RBT. There were no significant differences betweenthe positivity proportions in both moments of the study, therefore at the individual level seroconvertion it’ssuggesting that these individuals are at occupational risk and this will result, with a longer surveillanceperiod among this group in significative results.

A bruceloses é um problema de saúde pública no âmbito ocupacional de trabalhadores rurais eexecutores de programas de vacinação da doença no gado. A exploração da positividades e dos factoresassociados é necessária para estabelecer medidas preventivas na população trabalhadora. O objectivodeste trabalho foi determinar a seroprevalência e incidência de Bruceloses em vacinadores do programapara o controle da Bruceloses bovina no Departamento da Antioquia (Colômbia). Foi realizado um estudode tipo concorrente em vacinadores do programa de controle, com seguimento antes e depois do ciclo devacinação, com o propósito de determinar a seropositividade para bruceloses. Foi estimado a positividadecom os testes Rosa de Bengala e Elisa Competitivo. Para a primeira amostragem de 251 pessoas, o 10.8%(IC95% 6.4 % -14.3%) foram positivos a Rosa de Bengala. Na segunda amostragem, participaram 220pessoas, das quais o 15.4% (IC95%10.4 % -20.4%) resultaram positivas. Se observou uma seroconversãodo 5.75% (IC95% 2.0-9.5) para Rosa de Bengala. A positividade geral encontrada por Elisa Competitivopara a primeira amostragem foi do 25% (IC 95% 8.65 – 49.10), e para a segunda amostragem do 34.3%(IC95% 17.13 – 51.4). Foi observado uma seroconversão do 5.75% (IC 95% 2.002-9.493) para Rosa deBengala y do 38.5% (IC 95% 13.858-68.422). Não foram encontradas diferenças entre as proporções depositividade entre amostragens, embora, a seroconversão individual é um aspecto que pode dar resultadosdiferentes, ao realizar um seguimento mais prolongado de cada uma das variáveis.

[Knowledge and practices concerning taeniasis-cysticercosis in Colombian pig-breeders]. / Conocimiento y prácticas sobre teniasis-cisticercosis en una comunidad Colombiana.

OBJECTIVE: Describing knowledge and practices regarding taeniasis-cysticercosis and cysticercosis prevalence in the village of Andagoya, Colombia. METHODS: The study design was qualitative and quantitative. The study population consisted of pig breeders and their families, local groups and pigs. RESULTS: Study participants had partial knowledge of the taeniasis-cysticercosis complex. They considered taeniasis to be an illness resulting from faecal transmission and not caused by becoming infected with cysticercosis after consuming pork. Pig breeding is not carried out in confined conditions and, although breeders know the right measures for controlling some parasitic illnesses, these practices are not observed. There was 8.7% presence of T. solium antibodies in pig breeders and their relatives and 20.9% in the pigs. CONCLUSIONS: An educational programme aimed at raising the population's awareness of the taeniasis-cysticercosis complex cycle should be developed; this will facilitate control measures being applied.

Conocimiento y prácticas sobre Teniasis-cisticercosis en una comunidad colombiana / Knowledge and practices concerning taeniasis-cysticercosis in Colombian pig-breeders

Objetivo Determinar los conocimientos y prácticas sobre teniasis-cisticercosis y la frecuencia de anticuerpos contra Taenia solium en habitantes de la localidad de Andagoya, Colombia. Métodos Se realizó un estudio cualitativo-cuantitativo. Las poblaciones de estudio fueron los criadores de cerdos y sus familias, población local y cerdos. Resultados La población tiene un conocimiento parcial del complejo teniasis-cisticercosis. Identifica la cisticercosis como una enfermedad sólo del cerdo y no del humano, considera la teniasis como una enfermedad de transmisión fecal y no ocasionada por el consumo de carne de cerdo con cisticercosis. La crianza de cerdos no se hace en confinamiento y aunque se conocen los hábitos higiénicos para el control de enfermedades parasitarias su cumplimiento no es adecuado. La presencia de anticuerpos contra T. solium en los criadores de cerdos y sus familiares fue del 8,7 por ciento y en los cerdos del 20,9 por ciento. Conclusión Se debe desarrollar un programa educativo sobre teniasis-cisticercosis que permita sensibilizar a la población para el conocimiento y la aplicación de medidas de control.

Objective Describing knowledge and practices regarding taeniasis-cysticercosis and cysticercosis prevalence in the village of Andagoya, Colombia. Methods The study design was qualitative and quantitative. The study population consisted of pig breeders and their families, local groups and pigs. Results Study participants had partial knowledge of the taeniasis-cysticercosis complex. They considered taeniasis to be an illness resulting from faecal transmission and not caused by becoming infected with cysticercosis after consuming pork. Pig breeding is not carried out in confined conditions and, although breeders know the right measures for controlling some parasitic illnesses, these practices are not observed. There was 8.7 percent presence of T. solium antibodies in pig breeders and their relatives and 20.9 percent in the pigs. Conclusions An educational programme aimed at raising the population's awareness of the taeniasis-cysticercosis complex cycle should be developed; this will facilitate control measures being applied.

Validation of two rating scales for attention-deficit hyperactivity disorder diagnosis in Colombian children.

This study assesses the validity of the Behavioral Assessment System for Children-parent and teacher questionnaires for attention-deficit hyperactivity disorder diagnosis in a randomized sample of 344 Colombian children (145 cases, 199 controls), males and females, ages 6 to 11, with an estimated Wechsler Full Scale Intelligence Quotient over 70. The assessment protocol for both groups included psychiatric, neurologic, and psychological interviews, parent and teacher rating forms, and an Attention-Deficit Hyperactivity Disorder Checklist. All Behavioral Assessment System for Children-parent and teacher dimensions, except withdrawal and somatization, significantly differentiated cases and controls. Parents and teachers rated attention-deficit hyperactivity disorder combined type children as significantly more aggressive. Both questionnaires had good discriminant accuracy for detecting cases and control children, but accuracy for discriminating between attention-deficit hyperactivity disorder subtypes was poor. The Behavioral Assessment System for Children-parent and teacher questionnaires for 6- to 11-year-olds may be useful tools for diagnosing the presence of attention-deficit hyperactivity disorder. Additional assessment methods will be needed to discriminate between the subtypes.

D6S439 microsatellite identifies a new susceptibility region for primary Sjögren's syndrome.

OBJECTIVE: To examine genetic variations in the region surrounding loci of the major histocompatibility complex, and to investigate the probable location of a new candidate region on the short arm of chromosome 6 predisposing to primary Sjögren's syndrome (SS). METHODS: We conducted an association study and positional candidate gene approach by microsatellite analysis. Five polymorphic microsatellite markers, D6S273, D6S439, D6S1645, D6S291, and DS61019, spanning the region 6p21.3, and establishing particular landmarks to discriminate between the human leukocyte antigen class II and tumor necrosis factor-a loci, were genotyped by polymerase chain reaction technique. RESULTS: A total of 64 patients with primary SS and 120 matched controls were examined. There was no genetic stratification among cases and controls. Genotype distribution analysis disclosed a significantly higher number of homozygotes for D6S439 locus in patients than in controls [odds ratio (OR): 3, 95% confidence interval (CI): 1.46-6.14, p = 0.004]. Confirmation of this homozygosity was established by the gene correlation intra-locus test (Fis value = +0.233, p = 0.0007). Allele D6S439*274 was associated to disease (OR: 3, 95% CI: 1.35-6.65, p = 0.006, pc = 0.04). Among patients, no significant linkage disequilibrium (LD) value was found between the studied microsatellites and TAP, HLA-DRB1, or HLA-DQB1 loci. In controls, there was LD between D6S1645 and D6S291 loci. CONCLUSION: Our results indicate that D6S439 microsatellite defines a new susceptibility region for primary SS, independent of LD with TAP and HLA DQ/DR. These findings might imply that a gene surrounding this location is causally related to the disease.