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Yaws in the periurban settlements of Port Moresby, Papua New Guinea
HOPE worldwide (PNG), Port Moresby, Papua New Guinea
Yaws is a re-emerging disease in Papua New Guinea. A resurgence of yaws is documented
in the periurban settlements around Port Moresby. A total of 494 cases were identified from
April 2000 to September 2001. The age distribution ranged from 2 years to adult (median 9
years). Presenting symptoms were adequately recorded in 286 cases (58%). Of these, 42%
presented with raised painless sores, 47% with bone/joint symptoms only and 11% with both
sores and bone/joint symptoms. Children in communities with a suspected high prevalence
were surveyed and examined for presence of primary yaws sores. 33 out of 227 children
examined (15%) had evidence of primary yaws sores. Initial control measures have been case-
finding and treatment of contacts, but in areas of known high prevalence mass treatment is
planned.
Introduction
This spirochaete is morphologically,antigenically and genetically indistinguishable from T. pallidum var pallidum, the causative Guinea (PNG) before 1950. Between 1953 and 1956 an average of 16,186 cases were reported response and clinical features (7,8).
treatment campaign from 1953 to 1958markedly reduced the incidence of yaws.
Yaws is transmitted via skin to skin contact.
Yaws became a notifiable disease in 1969 with The role of flies and fomites in transmission is annual reported cases remaining less than 1000 unclear. Congenital transmission of yaws does per year until 1978. The majority of these affecting children in communities with poor Department of Health removed yaws from the hygiene. It has three clinical stages. There is a national reportable disease listing and interest in yaws waned. However, following reported lesion is a papule that develops into a round or leaving no scar. This lesion has also been Trobriand Islands (3), East New Britain, West termed framboiesia tropica. It usually resolves New Britain, New Ireland and West Province of the Solomon Islands (4), yaws was re-listed multiple secondary papillomatous lesions may as a reportable disease in 1984 (1). In 1984, 821 cases were reported (5), in 1989, 3421 lesions include dermatitis, hyperkeratosis of cases (6). Most outbreaks have been on the communities. To date, no reports have been dactylitis and juxta-articular inflammation may published detailing yaws outbreaks in urban or particularly at night. Chronic effusions mayoccur in synovium-lined cavities. Yaws is an infectious disease of the tropics caused by Treponema pallidum var pertenue.
After a latent period yaws may reappear in a HOPE worldwide (PNG), PO Box 3478, Boroko, NCD 111, Papua New Guinea tertiary form with necrotic destruction of skin, coming to their block (group of houses) and cartilage and bones resulting in gross deformity only 21% of dwellings have electricity. On average there are 6.8 people per dwelling.
People from every province of PNG live in the In early lesions T. pertenue may be seen on area (10). Yaws was first observed by clinic staff in 1995. From 1995 to 1998 there was a exudate from suspected lesions. Diagnosis in gradual increase in cases. During 1999 case the field is often made on clinical grounds Study design
Laboratories) flocculation test is a sensitivenontreponemal test. The antibody titres peak at The first part of the study involved clinic- about 10 months after initial infection.
based case detection at 9 Mile Clinic. Patients Treatment interrupts the peak levels. Antibody presenting to the clinic with signs or symptoms levels gradually decrease to normal over 9 months to 3 years (9). Reactive VDRL tests are confirmed by a treponemal-specific test defined as a clinical case of yaws with a positive VDRL and TPHA, were then noted in haemagglutination (TPHA) test. A negative the clinic register. The age, sex, clinical test in a person suspected of having secondary presentation and location of confirmed cases yaws excludes the diagnosis. Sensitivity is recorded. Previous studies have used a titre of positive predictive value of a positive VDRL positive predictive value of any VDRL titre and a positive TPHA, it was decided to use apositive TPHA in conjunction with a positive T. pertenue is still generally susceptible to penicillin. Benzathine penicillin is preferred as presentations were divided into the following: a single dose, producing a treponemocidal level for more than 3 weeks. It is stable in the tropics and available in multidose phials.
bone/joint symptoms together and ‘yawsunspecified’. The patients with ‘yaws In the Western Pacific Region a decreased unspecified’ were those in whom clinical response to benzathine penicillin has been presentation was not recorded accurately.
reported (6). Tetracycline, erythromycin and chloramphenicol would be appropriate second- known yaws cases who were brought in for a Study population
community prevalence survey of cutaneousyaws. This was carried out in July 2001, in The 9 Mile Urban Clinic serves a population of approximately 20,000 people (1998 figures) from 8 and 9 Mile settlements. The annualpopulation growth rate is estimated to be 7.2%.
There were four survey sites; Sabusa, Keto, However, patients also come regularly from Lareba and Laloki. The surveys were planned Erima, Sogeri District and communities along in advance to coincide with ‘local government’ the Hiritano Highway (Laloki, Sabusa, Brown day ensuring the presence of the majority of the population. The surveys were carried out atthe local meeting area of each community.
Residents’ access to utilities is limited even Consent was obtained from the local leaders in the established 8 and 9 Mile settlements.
and the survey explained in both Melanesian Pidgin and the local language. Children who were old enough to walk up to the age of 16 from 2 years old to adult (median 9 years). Of papules suggestive of yaws and a history taken the 494 cases, 31 cases did not have the age specifically asking about the presence of bone/joint symptoms suggestive of yaws. The remaining 463 confirmed cases is shown in survey was carried out by the nursing and Figure 2. Many adults in this population do not know their age. These were recorded as having ages greater than 20 years old. More than 90% of all cases were between 2 and 18 The clinical presentation of confirmed yaws Yaws cases identified were advised to come cases is shown in Table 1. Of the 286 cases (58%) in which there was a clear clinical injections. Family members were also advised raised yaws sores, 47% had bone/jointsymptoms only and the remaining 11% had From April 2000 until the end of September The VDRL titres of yaws cases are shown in Table 2. In 85% of the cases the VDRL titre identified and registered at the 9 Mile Urban was 16 or above. All cases had a positive depicted in Figure 1. The male to female ratioof the 486 confirmed cases of known sex was The results from the field surveys carried out are shown in Table 3. 227 children were Figure 1. Number of new yaws cases by month from April 2000 to September 2001 in the periurban settlements of PortMoresby, Papua New Guinea.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 20+ Figure 2. Age distribution of yaws cases in the periurban settlements of Port Moresby, Papua New Guinea.
examined in the four areas described. Of these, sores amongst the children examined was 7% 33 (15%) had active yaws sores. 20 (9%) gave a history of bone/joint symptoms suggestive ofyaws. The highest prevalence of active yaws Discussion
sores was in Sabusa. 26 (23%) of the 112children examined had evidence of a raised resurgence of yaws in the periurban settlements bone/joint symptoms in response to direct of Port Moresby, Papua New Guinea. A case questioning. In Lareba, a different location but series of 494 cases is documented. This is the with similar demographics and socioeconomic status to Sabusa, there were no yaws sores found in the 19 children that were examined.
resurgence has been previously documented on In Keto and Laloki the prevalence of yaws the New Guinea Islands and in rural areas.
CLINICAL PRESENTATION OF YAWS CASES IN THE PERIURBAN SETTLEMENTS OF PORT MORESBY, PAPUA Clinical presentation
Number of yaws cases
Percentage
hard to interpret as the numbers may have beenaffected by an increasing awareness amongst VDRL TITRES OF YAWS CASES IN THE PERIURBAN the patients and their families. Clinic staff awareness and interest in the disease may also have affected the results. One may expect anincrease in numbers during the dry season VDRL titre
Number of
Percentage
yaws cases
The age distribution of cases is similar to that discussed in the literature. 90% were aged between 2 and 18 years old. There may well have been some overlap and diagnosticinaccuracies in the adults presenting with ‘yaws’ and syphilis as they both are diagnosedby a positive VDRL and TPHA. Clinically, the The periurban settlements of Port Moresby rashes of secondary syphilis and secondary in 2001 provide an ideal environment for yaws yaws in adults may also be similar. However, transmission. There is a young, highly mobile benzathine penicillin is appropriate treatment and rapidly increasing population, with people originating from throughout PNG. Otherfactors that could promote the spread of yaws ‘Yaws unspecified’ was the most common include lack of access to water, the decreasing classification of clinical presentation and reflected a number of issues. Firstly, some of immunologically naive population susceptible these patients were symptomatic contacts of known yaws patients who had positive VDRLtests and were treated for yaws. Secondly, due The impact of yaws on communities is hard to staff shortages the data entry was not always to assess. The tertiary form of yaws can result in grossly disfiguring, destructive lesions ofskin and bones. However, these tend to occur 10 to 15 years after the initial infection. We was a clear clinical presentation documented, 47% had bone/joint symptoms alone, and 11% had bone/joint symptoms in association with yaws sores at presentation. It has been the observation of the clinic staff that for a childfrom this area who presents with sore joints or bones, with no history of injury and without PREVALENCE SURVEY OF YAWS CASES AMONGST CHILDREN UNDER 16 YEARS OLD IN 4 PERIURBAN SETTLEMENTS OF PORT MORESBY, PAPUA NEW GUINEA Location
Number with
Number with
yaws sores
painful joints
examined
WORLD HEALTH ORGANIZATION RECOMMENDED POLICY FOR YAWS Percentage of population
Prevalence of active yaws
Recommended treatment
serologically positive
sores in community
Total mass treatment withbenzathine penicillin Mass treatment for all juveniles<15 years old, cases and knowncontacts with benzathinepenicillin Treatment of cases and knowncontacts with benzathinepenicillin signs of sepsis or rheumatic fever, the likely guidelines in that only juveniles less than 16 joints are wrists, elbows, knees and ankles.
presence in Sabusa of 23% of juveniles with symmetrical pattern. The possibility exists, bone/joint symptoms is an indication that yaws therefore, that an outbreak of yaws may be reported as an outbreak of oligoarthritis,arthralgias or ‘sore knees and ankles’. population of Sabusa is less than 16 years old and that 90% of yaws cases are in the younger Technical Reports advise that in areas of age groups, the WHO recommendations would known endemicity the prevalence of cutaneous suggest that a mass treatment campaign is yaws can be used as a guide for community indicated for the children of Sabusa. This is currently being planned. Other areas within 8 and 9 Mile settlements, and the other periurban guide, but is more difficult in rural areas than surveyed to assess the yaws burden and therequirement for mass treatment.
shown in Table 4. Each community withactive yaws should be assessed annually. At Conclusions
least 80% of the population should be assessedeach time. When <0.5% of the population has active yaws, the mass treatment phase settles New Guinea. The majority of cases occur in children. Clinicians in PNG should be awarethat patients with yaws often present with bone/joint pains in the absence of sores. Yaws initially an attempt to control the disease with is once again a significant public health issue case-finding only. They were carried out in throughout PNG. It is treated easily with a areas thought by the clinic staff to have a high single dose of penicillin and there are clear guidelines regarding community assessment relative ethnic and climatic homogeneity there and control. Thus, yaws requires resources and survey was not done in accordance with WHO ACKNOWLEDGEMENTS
Report 1984. Port Moresby: Department of Health,1984.
Thanks to the nursing staff of 9 Mile Clinic 6 Meheus A, Antal GM. The endemic treponematoses:
not yet eradicated. World Health Stat Q 1992;45: and the staff of HOPE worldwide (PNG) for data collection and support. Also thanks to 7 Wicher K, Wicher V, Abbruscato F, Baughn RE.
Professor John Vince for wise and helpful Treponema pallidum subsp. pertenue displays pathogenic properties different from those of T.
pallidum subsp. pallidum. Infect Immun2000;68:3219-3225.
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