Relationship between bite-to-hospital time and morbidity in victims of carpet viper bite in North-Central Nigeria.

BACKGROUND

Envenomation from snake bites is a public health hazard in tropical countries. The observed mortality among in-hospital patients bitten by carpet viper (Echis ocellatus) in northern Nigeria has drastically reduced, related to the use of a mono-specific ovine Fab anti-snake venom. However, many victims survive with temporary or permanent physical or psychological sequelae.

OBJECTIVE

Our aim was to find the relationship between bite-to-hospital time and morbidity in patients bitten by carpet viper.

METHODS

A prospective study was conducted in North-Central Nigeria. The signs of morbidity scored were oedema, tenderness, prolonged whole blood clotting time, blister, ulcer, need for blood transfusion, coma, hypotension, convulsion, length of hospital stay, need for disarticulation, and need for skin graft. A score of 1 was given to each objective and verifiable sign. Bite-to-hospital time of 233 subjects was obtained.

RESULTS

Most of the subjects, 150(64%) came to the hospital within six hours of snake bite, out of whom two(1%) came within one hour. The median bite-to-hospital time was five hours with a range of 0.5-216 hours. Major morbidities were oedema accounting for 212 (91.0%; 95% CI =86.6-94.3%). incoagulable blood was seen in 205(88%; 95% CI = 83.1-91.9%) and tenderness in 201(86.3%; 95% CI = 81.2-90.4%). The mean morbidity score was 8 ± 4. For every unit increase in log bite-to-hospital time, the morbidity score increased by 1.85 (p < 0.001).

CONCLUSIONS

Morbidity caused by carpet viper bite is high in Nigeria and worsens with increasing bite-to-hospital time.