Molecular detection of Leptospira interrogans serovar Hardjo from cattle and goats in Maiduguri, Nigeria

Leptospirosis is an important zoonotic disease of livestock with a worldwide distribution. The prevalence of Leptospirosis is often associated with infertility, abortion, retention of fetal membrane, decreased milk production, and early neonatal mortality in livestock. Leptospira interrogans serovars Pomona, Canicola, Bratislava, Grippotyphosa, Hardjo, and Icterohemorrhagiae are the most common causes of infection in various hosts. This study aimed to determine the genetic characteristics of Leptospira interrogans serovar Hardjo associated with reproductive losses in cattle and goats in Maiduguri, Nigeria. A total of 376 blood samples (188 each from cattle and goats) were collected, and 30 sera consisting of 12 ELISA-positive and 18 negative sera were subjected to phenol-chloroform DNA extraction and conventional PCR amplification, targeting the LipL32 structural gene of L. interrogans. All seropositive samples tested negative for PCR, while one seronegative sample tested positive for PCR. The PCR-positive sample yielded a 423bp amplicon size, and sequence analysis of the positive DNA showed 98.4% to 99.6% similarity with other Leptospira Hardjo sequences deposited in the GenBank. This study is, to the best of our knowledge, the first report on the genetic characteristics of the field serovar of Leptospira interrogans serovar Hardjo circulating in cattle and goats with reproductive problems in northeastern Nigeria. Further studies are required to elucidate the full spectrum of the molecular epidemiology of Leptospira Hardjo in Nigeria.