Mass Treatment with Single-Dose Azithromycin for Yaws

Kristi Tinsbloom, PharmD candidate 2015,  Mercer University College of Pharmacy

Yaws is a disease caused by the bacteria Treponema pallidum subspecies pertenue. It is typically found in tropical forest areas in Africa, Asia, and Latin America. It is transmitted by direct contact (non-sexual) with the fluid from a lesion on an infected person. Lesions are normally found on the limbs. This disease is more prominent in poor communities and children under 15 years of age account for approximately 75% of cases. Yaws affects the skin, bone, and cartilage; if not treated, the infection can progress and cause disability and disfigurement.1

According to the World Health Organization (WHO), there are two acceptable treatments for yaws, azithromycin 30 mg/kg single oral dose or benzathine penicillin intramuscular dose of 1.2 million units for adults or 600,000 units for children.1 A recently published study investigates the efficacy of mass treatment with single-dose azithromycin to stop the transmission of yaws. This is a strategy developed by the WHO. However, before the implementation of mass treatment on a global scale (in areas affected by yaws), data is needed to support the strategy.2

Title: Mass Treatment with Single-Dose Azithromycin for Yaws2
Design Open-label; 13,490 participants
Objective To collect data on the effectiveness of the WHO strategy to eliminate yaws in affected areas worldwide
Study groups One group – received drug treatment
Methods Azithromycin 30 mg/kg (max 2 grams) was offered to all people greater than 2 months within the selected villages in Papua New Guinea. Pregnant women and those with a known allergy to macrolide antibiotics were offered penicillin G Benzathine 50,000 units/kg intramuscularly. Follow-up was performed every 6 months that consisted of clinical examination of the population in the villages. All persons examined having active yaws were treated, along with their contacts.
Duration April 2013 through May 2014
Primary Outcome Measure Prevalence of serologically confirmed active infectious yaws in the entire population and the presence of latent yaws with high-titer seroreactivity (rapid plasma reagin [RPR] greater than or equal to 1:16) in a subgroup of children 1 to 15 years of age, at baseline and at 6 and 12 months
Baseline Characteristics Not Applicable
Results There were 13,302 participants that received azithromycin, 177 that received penicillin G Benzathine, and 11 declined treatment. The overall rate of treatment coverage was 83.8% (all villages had a coverage rate greater than 70%). The prevalence of active yaws infections confirmed by serological tests decreased from 2.4% at baseline to 0.3% at 6 months and remained 0.3% at 12 months (P<0.001). High-titer latent yaws in children decreased from 18.3% at baseline to 6.5% at 12 months (P<0.001).
Adverse Events Common Adverse Events: nausea or abdominal pain (9.5%), diarrhea (7.9%), vomiting (4.7%)
*These adverse events were obtained from 316 participants in 60 households during active surveillance.
Serious Adverse Events: None reported
Percentage that Discontinued due to Adverse Evens: None reported
Study Author Conclusions Twelve months after mass treatment with azithromycin, the prevalence of active and latent yaws decreased substantially. Follow-up examinations to identify and treat active cases of yaws may have helped in reducing the prevalence of yaws. The study authors conclude that their findings support the WHO strategy for mass treatment to eradicate yaws.

This study aimed to validate the treatment strategy developed by the WHO for the eradication of yaws. The authors suggest that to effectively suppress the disease and its transmission, treatment coverage would need to be greater than 80%. The WHO recommends 100% coverage during the initial mass treatment. It is not known how many follow-up surveys/examinations would need to be conducted in order to eliminate yaws. The authors also reported no observance of macrolide resistance in this particular subspecies of T. pallidum. This strategy may very well be a great option for halting the transmission and eventually eliminating yaws altogether.

Advertisements

One thought on “Mass Treatment with Single-Dose Azithromycin for Yaws

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s