Infectivity of secondary dapsone-resistant cases

Area of Science:

• Infectious Diseases
• Microbiology
• Public Health

Background:

• Dapsone remains a cornerstone of leprosy treatment.
• Secondary dapsone resistance poses a significant challenge to leprosy control.
• Understanding transmission patterns of drug-resistant leprosy is crucial.

Purpose of the Study:

• To determine the incidence of leprosy among household contacts of individuals with secondary dapsone resistance.
• To assess the prevalence of primary dapsone resistance in contacts who developed leprosy.
• To evaluate dapsone resistance in paucibacillary leprosy cases treated with monotherapy.

Main Methods:

• Study involved 517 household contacts of 113 leprosy cases with secondary dapsone resistance.
• Calculated leprosy incidence rate per 1000 person years at risk.
• Assessed dapsone resistance in contacts who developed multibacillary and paucibacillary leprosy.

Main Results:

• Leprosy incidence rate was 4.3 per 1000 person years at risk, comparable to contacts of lepromatous cases (4.8).
• Two to three cases of primary dapsone resistance were identified among 27 contacts with multibacillary leprosy.
• No dapsone resistance was found in 48 paucibacillary leprosy cases treated with dapsone monotherapy.

Conclusions:

• Secondary dapsone-resistant leprosy cases may pose a similar transmission risk as lepromatous leprosy.
• Primary dapsone resistance can emerge in contacts, particularly in multibacillary forms.
• Further research is needed to investigate the potential increase in primary dapsone resistance due to secondary resistant cases.