Sero-epidemiology of peste des petits ruminants in Oromia and Afar regional states of Ethiopia.

Peste des petits ruminants (PPR) is a severe non-zoonotic viral disease of small ruminants caused by a morbillivirus closely related to rinderpest virus (RPV). The disease is widespread in Africa, the Middle East and Southern Asia. It is one of the priority animal diseases whose control is considered important for poverty alleviation in those regions because of the associated high economic losses. A sero-epidemiological study of PPR was conducted in Oromia and Afar regional states of Ethiopia. A total of 800 serum samples from sheep and goats were collected between October 2015 and March 2016 in Afar and Oromia, where no vaccination history has been recorded. These two regions are known to have a large population of small ruminants. The levels of PPR antibodies obtained in the two regions using the competitive enzyme-linked immunosorbent assay (cELISA) ID Screen® PPR Competition from IDvet (Montpellier, France) were similar, at 12.7% and 13.0% for Afar and Oromia, respectively. A seroprevalence of 12.9% for the two regions was obtained. The study also linked seropositivity to risk factors such as sex, age and species with a p-value of less than 0.05 (p = 0.0001, p = 0.0001 and p = 0.004, respectively).

La peste des petits ruminants (PPR) est une maladie virale non zoonotique des petits ruminants due à un morbillivirus apparenté au virus de la peste bovine. Cette maladie est très présente en Afrique, au Moyen-Orient et en Asie du Sud. Elle fait partie des maladies animales prioritaires qu'il est important de contrôler à des fins d'allègement de la pauvreté dans les régions affectées, en raison de l'ampleur des pertes économiques qui lui sont associées. Une étude séroépidémiologique sur la PPR a été conduite en éthiopie, couvrant les régions d'Oromia et d'Afar. Au total, 800 échantillons sériques issus d'ovins et de caprins ont été prélevés entre octobre 2015 et mars 2016 à Afar et Oromia, régions sans historique documenté de vaccination. Les populations de petits ruminants y sont nombreuses. La détection d'anticorps dirigés contre le virus de la PPR au moyen de l'épreuve immuno-enzymatique de compétition (cELISA) ID Screen® PPR Competition du laboratoire IDvet (Montpellier, France) a fait apparaître un niveau d'anticorps comparable dans les deux régions (12,7 % à Afar et 13,0 % à Oromia). Le taux de prévalence sérologique pour les deux régions était de 12,9 %. L'étude a également permis de relier la présence d'anticorps à certains facteurs de risque tels que le sexe, l'âge et l'espèce, avec un degré de signification (p) inférieur à 0,05 (respectivement, p = 0,0001, p = 0,0001 et p = 0,004).

La peste de pequeños rumiantes (PPR) es una grave enfermedad viral no zoonótica que afecta a los pequeños rumiantes, causada por un morbilivirus estrechamente emparentado con el virus de la peste bovina. Esta patología, muy extendida en África, Oriente Medio y el sur de Asia, es una de las enfermedades animales prioritarias cuyo control se considera importante para paliar la pobreza en esas regiones, dado que engendra cuantiosas pérdidas económicas. Los autores describen un estudio seroepidemiológico de la PPR efectuado en los estados regionales de Oromia y Afar (Etiopía). Entre octubre de 2015 y marzo de 2016 se reunieron en total 800 muestras séricas de ovejas y cabras de Afar u Oromia, regiones donde no se tiene registrado antecedente alguno de vacunación y donde se sabe que hay una numerosa cabaña de pequeños rumiantes. En ambas regiones, con aplicación del ensayo inmunoenzimático de competición (ELISAc) ID Screen® PPR Competition de IDvet (Montpellier, Francia), se obtuvieron niveles similares de anticuerpos contra el virus de la PPR: del 12,7% en Afar y del 13,0% en Oromia. El cálculo arroja una seroprevalencia del 12,9% en ambas regiones. El estudio puso también de relieve la existencia de un vínculo entre seropositividad y tres factores de riesgo, el sexo, la edad y la especie, con valores de p inferiores a 0,05 (respectivamente, p = 0,0001, p = 0,0001 y p = 0,004).

Detection of phytoplasma by loop-mediated isothermal amplification of DNA (LAMP).

Napier stunt phytoplasma (16SrXI and 16SrIII) in eastern Africa is a serious threat to the expansion of Napier grass (Pennisetum purpureum) farming in the region, where it is widely cultivated as fodder in zero grazing livestock systems. The grass has high potential for bio-fuel production, and has been adopted by farmers as a countermeasure to cereal stem borer Lepidoptera, since it attracts and traps the insect. Diagnosis of stunt phytoplasma have been largely by nested polymerase chain reaction (nPCR) targeting the 16S rRNA gene. However, the method is laborious, costly and technically demanding. This investigation has developed a simpler but effective phytoplasma diagnostic tool, called; loop-mediated isothermal amplification of DNA (LAMP). The assay was tested on 8 symptomatic and 8 asymptomatic plants, while its detection limit was compared to nested PCR using samples serially diluted from 3 ng/µl to 0.38 pg/µl. Molecular typing of LAMP products was determined by BsrI restriction digestion and Southern blot analysis. The assay sensitivity, positive and negative predictive values were estimated, while the specificity was tested on 11 phytoplasma groups. LAMP was specific to 5 phytoplasma groups: 16SrVI, X, XI and XVI. BsrI restriction digestion produced two predicted fragments, and there was specific binding of probe DNA to the LAMP amplicons in Southern blot analysis. The assay sensitivity was 100%, while the positive and negative predictive values were 63 and 100% respectively. LAMP was 20-fold more sensitive than nested PCR. This study validates LAMP for routine diagnosis of Napier stunt and other closely related phytoplasmas.