General characterization of venom from the Moroccan snakes Macrovipera mauritanica and Cerastes cerastes

Abstract

Ophidian envenomation accidents constitute a serious public health problem in many countries around the globe. Over 5 million such accident cases occur each year causing more than 100,000 deaths. In Africa, more than 20,000 deaths per year are registered while 400,000 envenomation victims retain severe and permanent functional sequelae. In Morocco, snakebites are frequent and of greater severity in children. They occur mostly in rural areas. The incidence of these bites remains poorly understood and vastly underestimated. The epidemiological data are not well known due to the absence of a national registry, whereas a significant proportion of envenomations receive only traditional treatment methods in non-medical intensive care. This prompted us to investigate the enzymatic and biological properties of venom biochemical constituents from two of the most dangerous snake venoms in Morocco: Cerastes cerastes (Cc) and Macrovipera mauritanica (Mm). Also, we studied the immune cross-reactivity of Cc and Mm venoms in comparison to that of another important dangerous Moroccan viper, Bitis arietans (Ba), to identify the best candidates (venom or a mixture of venoms) for producing the most efficient and protective antivenom. In the present study, we report a preliminary venom characterization of Cc and Mm and the cross-reactivity that may exist between their venoms and Ba. These venoms are known to be highly toxic and contain several proteins that differ by molecular weights. Interestingly, both Cc and Mm venoms are characterized by intense hemorrhagic and phospholipase A2 activities and their ability to degrade the α and γ chains of fibrinogen. They display very low proteolysis through the casein test. After injection into mice, Cc and Mm induce myonecrosis in skeletal muscles, which most likely reflects direct action of myotoxins and indirect action of hemorrhagic molecules present in these venoms. In mice, this myonecrosis diminishes serum creatine phosphokinase (CPK) levels. As expected, Cc venom is immunogenic and induces highly protective antivenom against Mm and Ba venom antigens. This protective capacity is similar to that of the antivenom produced against the Mm venom.

Keywords

• Cerastes cerastes
• Macrovipera mauritanica
• snake venom
• characterization
• biological activities
• cross-reaction