Validation of the Roche AMPLICOR HIV DNA test version 1.5 for early infant diagnosis of HIV in Papua New Guinea

Human immunodeficiency virus (HIV) is a significant public health issue in Papua New Guinea (PNG). After heterosexual transmission (90%), the second most common route of transmission is vertically from mother to child (3.5%). Before the introduction of molecular methods of HIV testing in PNG, diagnosing exposed infants was problematic because there were no reliable assays available for accurate early infant HIV detection. This study aimed to validate and assess a global gold standard for virological early infant HIV diagnosis in PNG: the AMPLICOR HIV DNA v1.5 assay (Roche) using dried blood spot (DBS) specimens. The assay was validated in three ways: by testing well-characterized DBS and kit controls and by blinded retesting of 42 patient specimens. The assay was further investigated by comparison with a serological assay. The results indicated that the assay was robust and highly reproducible using DBS and kit controls, with 100% sensitivity and specificity. Of the 42 infant DBS specimens that were retested blindly, 100% of the test results were concordant with diagnostic results. Among the 42 infant specimens tested with the Amplicor HIV DNA v1.5 assay we found that 33% of infants (n = 14) were HIV PCR positive and 67% (n = 28) negative. The earliest point of HIV detection established for this study was three months of age. This pilot study indicates that HIV-infected infants in PNG can be effectively diagnosed using virological testing and can thus be started earlier on treatment than was previously possible with serological testing.

Bacterial, viral and parasitic aetiology of paediatric diarrhoea in the highlands of Papua New Guinea

Enteropathogens and clinical features associated with diarrhoea were investigated in 1526 children admitted over a 5-year period to the paediatric ward of a hospital in the highlands of Papua New Guinea. Overall, a recognized pathogen was isolated from 39 per cent of the children admitted with diarrhoea. The most commonly isolated agents were rotavirus (23 per cent), Shigella spp. (13 per cent), Campylobacter spp. (12 per cent), Cryptosporidium parvum (10 per cent) and enteropathogenic Escherichia coli (8 per cent). The clearest clinical associations were rotavirus with vomiting, and Shigella with blood and pus in the stool. A control series of children admitted with other complaints was also included, and the odds ratios for diarrhoea for the above five pathogens were 18.2, 9.6, 3.7, 2.2, and 1.6, respectively.

Bacterial and viral etiology of severe infection in children less than three months old in the highlands of Papua New Guinea

OBJECTIVE

Determine the bacterial and viral etiology of severe infection in young Papua New Guinean infants as part of a multicenter study in four developing countries aimed at improving case management guidelines.

METHODS

Between March, 1991, and April, 1993, children aged <3 months were recruited at the outpatient department of Goroka Base Hospital, Papua New Guinea (PNG). Children with pre-defined inclusion criteria were enrolled, a history was taken and clinical examination was performed. Blood and urine were collected from children with signs suggestive of severe disease together with eye, umbilical and pernasal swabs as appropriate. Nasopharyngeal aspirates (NPAs) were collected from children with and without signs of severe disease for identification of viruses and Chlamydia trachomatis by direct fluorescent antibody staining.

RESULTS

3280 infants were triaged and 2168 enrolled, among whom 968 had signs suggestive of severe disease. Group A Streptococcus (Streptococcus pyogenes) and Staphylococcus aureus were the most important bacterial pathogens isolated from children < 1 month old with severe infections, and Streptococcus pneumoniae, S. pyogenes and Staphylococcus aureus were most important in older children. Of 292 eye swabs 19 (7%) grew Neisseria gonorrhoeae. Of 116 umbilical swabs 51 (44%) grew S. pyogenes and 45 (39%) grew Staphylococcus aureus. Respiratory syncytial virus was the most important viral cause of acute lower respiratory infection.

CONCLUSIONS

S. pyogenes, S. pneumoniae and Staphylococcus aureus are important causes of severe infection in young children in the PNG highlands. It is necessary to improve access to clean water, promote hand-washing in the hospital and at home and investigate further the use of maternal immunization for the prevention of severe disease in young infants.

Aetiology and clinical signs of bacterial meningitis in children admitted to Goroka Base Hospital, Papua New Guinea, 1989-1992

Children aged 1-59 months admitted to Goroka Base Hospital with signs suggestive of meningitis were recruited to determine what proportion of such children have clinical or bacterial meningitis and to investigate the bacterial aetiology. A laboratory classification of definite, probable, possible, indeterminate and no meningitis was established. Thirty per cent of 697 children had a final clinical diagnosis of meningitis, 12% had culture-proven bacterial meningitis (case fatality rate 34%) and 10% had probable or possible meningitis. Inability to feed, vomiting, drowsiness, "staring eyes" and haemoglobin < 9 g/dl in addition to the classical signs of meningitis were associated with increased mortality. Isolates from cerebrospinal fluid were 62 pneumococci, 22 Haemophilus influenzae type b (Hib) and one Neisseria meningitidis. Including blood culture-proven and antigen-proven Hib disease, Hib and pneumococci accounted for 44% and 46% of bacterial meningitis, respectively, and 23% of pneumococci were intermediately resistant to penicillin. Inability to feed, bulging fontanelle, convulsions in young children, neck stiffness, fever and "staring eyes" were all independently associated with bacterial meningitis. Conjugate Hib vaccine must be given to infants as early as possible. Conjugate pneumococcal vaccines, maternal immunization with 23-valent vaccine and pneumococcal protein vaccines are under investigation for prevention of pneumococcal disease.

Community based study of sexually transmitted diseases in rural women in the highlands of Papua New Guinea: prevalence and risk factors

OBJECTIVE

To estimate the prevalence of sexually transmitted diseases (STDs) and determine their risk factors/markers among a rural population of women in the highlands of Papua New Guinea.

METHODS

Community based random cluster sample of women of reproductive age were interviewed and examined and had specimens collected for laboratory confirmation of chlamydial and trichomonal infection, gonorrhoea, syphilis, and bacterial vaginosis.

RESULTS

Chlamydia trachomatis was detected in 26%, Trichomonas vaginalis in 46%, Neisseria gonorrhoeae in 1%, syphilis in 4%, pelvic inflammatory disease (PID) (diagnosed clinically) in 14%, and bacterial vaginosis in 9% of 201 women. 59% of the women had at least one STD. In a multivariate logistic regression analysis taking the clustered sampling into account, independent risk factors for chlamydial infection were age < or = 25 years, < four living children, visualization of yellow mucopurulent endocervical secretions on a white swab, and bacterial vaginosis. Being married to a man who did not have other wives was protective. For trichomonal infection, independent risk factors were having no formal education, infertility, more than one sexual partner in the previous 12 months, treatment for genital complaints in the previous 3 months, abnormal vaginal discharge detected on examination, and chlamydial infection. Similar levels of trichomonal infection were found in all age groups. Among married women, rates of infection correlated with their perception of their husband having had other sexual partners in the previous 3 months, and this relationship was significant for chlamydial infection among women over 25.

CONCLUSION

STDs are a major problem in this population, with the risk factors varying by outcome. Current treatment regimens are inappropriate given the high prevalence of trichomonal infection, and the available services are inadequate. Effective interventions are required urgently to reduce this burden and to prevent the rapid transmission of HIV.

Screening for sexually transmitted diseases in rural women in Papua New Guinea: are WHO therapeutic algorithms appropriate for case detection?

The presence of a large reservoir of untreated sexually transmitted diseases (STDs) in developing countries has prompted a number of suggestions for improving case detection, including the use of clinical algorithms and risk assessments to identify women likely to be infected when they present to clinics for other reasons. We used data from a community-based study of STDs to develop and evaluate algorithms for detection of cervical infection with Chlamydia trachomatis or Neisseria gonorrhoeae, and for detection of vaginal infection with Trichomonas vaginalis or bacterial vaginosis. The algorithms were derived using data from 192 randomly selected women, then evaluated on 200 self-selected women. We evaluated the WHO algorithm for vaginal discharge in both groups. The prevalences of cervical and vaginal infection in the randomly selected group were 27% and 50%, respectively, and 23% and 52%, respectively, in the self-selected group. The derived algorithms had high sensitivities in both groups, but poor specificities in the self-selected women, and the positive predictive values were unacceptably low. The WHO algorithms had extremely low sensitivity for detecting either vaginal or cervical infection because relatively few women reported vaginal discharge. Simple algorithms and risk assessments are not valid for case detection in this population.

High prevalence of trichomonal vaginitis and chlamydial cervicitis among a rural population in the highlands of Papua New Guinea

We conducted a community-based study of the prevalence of sexually transmitted diseases in rural and periurban communities in Eastern Highlands Province. We interviewed a stratified random sample of women and men, examined the women for evidence of sexually transmitted diseases (STDs) and collected specimens for diagnosis of syphilis, by serology and dark-field microscopy, gonorrhoea, by Gram stain and culture, chlamydial infection, by polymerase chain reaction (PCR) and direct immunofluorescence (DIF), trichomoniasis, by wet mount, and bacterial vaginosis, by wet mount and Gram stain. The men were tested for chlamydial infection only (first void urine tested by PCR and DIF). 201 women and 169 men were tested. Additionally, adults in the same communities who had not been randomly selected were offered the same services. An extra 243 women and 85 men were tested in this way. The laboratory results confirmed the clinical impression of an extremely high prevalence of STDs in this population. Among those randomly selected, 46% of the women had trichomonal vaginal infections and 26% had Chlamydia trachomatis infections detected by PCR, while 25% of the men had chlamydial infections. Other infections were much less common. 58% had one or more STDs. The prevalence of infection in self-selected adults was similar to that found in those randomly selected.

A survey of sexually transmitted diseases in five STD clinics in Papua New Guinea

The first multicentre survey of sexually transmitted diseases (STDs) performed in Papua New Guinea was conducted in STD clinics in five towns, Port Moresby, Goroka, Rabaul, Lae and Daru, from September 1989 to May 1990. Infections with Neisseria gonorrhoeae and Chlamydia trachomatis (alone or in combination) were common. Penicillinase-producing N. gonorrhoeae (PPNG) represented 44% of all gonococcal isolates but significant intrinsic resistance to penicillin was not found. Of the other antibiotics tested, significant elevation of minimum inhibitory concentration (MIC) was common only for tetracycline, although no high-level tetracycline resistance was detected. C. trachomatis was detected by direct immunofluorescence (DIF) in 26% of 210 males and 27% of 64 females. 10% (21/210) of males and 11% (7/64) of females were both DIF positive for C. trachomatis and culture positive for N. gonorrhoeae. Of 203 males and 78 females tested, 5% and 12%, respectively, had serological evidence of current syphilis infection. Clinically, genital ulcer disease was most commonly due to syphilis, donovanosis or genital herpes, while specific vaginal infections were commonly seen in female patients attending Port Moresby and Lae STD clinics.

Arthritis in the highlands of Papua New Guinea

Acute polyarthritis is an important cause of morbidity in many tropical countries. Classification has often been difficult, with the term tropical polyarthritis used for those in whom a diagnosis could not be made. The implication that this is a distinct entity is probably incorrect, with likely causes being septic arthritis or post-infective reactive arthritis. This study aimed to determine the types of arthritis found in 43 patients (30 men) presenting consecutively to the Goroka Base Hospital in the Eastern Highlands of Papua New Guinea. Gonococcal arthritis was diagnosed in eight patients (six men) on the basis of isolation of Neisseria gonorrhoeae from the joint aspirate. In all cases the N gonorrhoeae was identified by the closed culture system on chocolate agar, but not always by routine plating. There were no specific clinical features that identified patients with a gonococcal septic arthritis. The remaining 34 patients had an undifferentiated oligoarthritis. The pattern of arthritis in men and women was of a lower limb pauciarticular arthritis with a predilection for the knee and ankle joints. A total of 30% of male patients had a history of urethral discharge and 44% of all patients had preceding diarrhoea. Arthritis was the only feature in 59% of patients and in 32% there was an associated enthesitis. In this study most patients had an oligoarthritis consistent with a reactive arthritis or a septic arthritis due to N gonorrhoeae. Broth inoculation of synovial fluid was the best method to isolate N gonorrhoeae, with standard methods for gonococcal isolation failing in some patients. It is recommended that the term 'tropical polyarthritis' is no longer used as it does not refer to a specific entity but consists of several known arthritides.

Bacterial colonization of the upper respiratory tract and its association with acute lower respiratory tract infections in Highland children of Papua New Guinea

Acute lower respiratory tract infection (ALRI) is the major cause of death among children in Papua New Guinea. This longitudinal study reports the bacteriologic findings for children observed in their hamlets. A total of 1,449 nasal swab specimens from 158 children less than 5 years of age who were studied intensively for 18 months were examined. Non-serotypable strains of Haemophilus influenzae were isolated from 91% of specimens, and serotypable strains were isolated from 35% (8% H. influenzae type b) of specimens. All children had acquired Streptococcus pneumoniae by the age of 3 months. The most frequently occurring serotypes of S. pneumoniae were 6, 19, and 23. Children more frequently carried invasive pneumococci during an episode of ALRI than when they were healthy. Also, children more frequently carried serotypable strains of H. influenzae during the 2 weeks preceding an episode of ALRI than when they were healthy. Between-children analyses showed that children who were susceptible to attacks of ALRI and those who were not susceptible had similar rates of carriage of bacteria.

Viruses associated with acute lower respiratory tract infections in children from the eastern highlands of Papua New Guinea (1983-1985)

This study, conducted at Goroka Hospital from January 1983 to June 1985, examined the viruses identified in nasopharyngeal aspirates (NPA) and urines collected from 716 hospitalised children with moderate or severe pneumonia, in NPA from 170 children with mild pneumonia treated as outpatients and in NPA from a control group of 428 children attending the outpatient department of Goroka Hospital suffering from minor ailments other than upper or lower respiratory tract infections. One or more viruses were identified from 68%, 51% and 43% of children with moderate or severe pneumonia, mild pneumonia and the control group, respectively. One-third of viruses were identified in conjunction with another virus in both control and sick children. Viral identification rates were highest in children under 1 year of age. Cytomegalovirus, adenoviruses, respiratory syncytial virus (RSV), measles and rhinoviruses were the most frequently identified viruses. RSV was associated with mild as well as moderate and severe disease. No virus was associated with an increased risk of death. Annual epidemics of RSV occurred during the wet season. An epidemic of influenza A virus and also influenza B virus and 3 epidemics of parainfluenza 3 virus occurred during the study period. The high viral identification rates in this study suggest a high frequency of transmission associated with the social structure and environment of Papua New Guinean highland villages and high population mobility.

The bacteriology of skin sores in Goroka children

The bacteriology of infected skin lesions was studied in paediatric outpatients. Thirty-nine untreated lesions were studied: 37 (95%) grew beta haemolytic streptococci (46% group A, 3% group B, 23% group C, 26% group G), 21 (54%) grew Staphylococcus aureus and 13 (33%) grew Corynebacterium haemolyticum. No attempt was made to selectively isolate Corynebacterium diphtheriae in this study. Vincent's organisms were seen in 13 (37%) of 35 gram stains from untreated lesions, including eight (73%) of 11 tropical ulcers. Twenty-three (92%) of the 25 strains of S. aureus isolated from untreated sores were resistant to penicillin.

Distribution and relationship to serotype of Haemophilus influenzae biotypes isolated from upper respiratory tracts of children and adults in Papua New Guinea

The relationship between serotypes and biotypes of 505 carriage strains of Haemophilus influenzae isolated from the upper respiratory tracts of well children, children with pneumonia, and healthy adults was studied. All except serotype c were significantly associated with one or two specific biotypes (P less than 0.001). No encapsulated organisms belonging to biotypes V, VI, or VII were encountered. No significant difference in the interaction of biotypes and serotypes isolated from well and sick children was present. Both encapsulated and nonserotypable biotype I H. influenzae strains were commonly carried in the upper respiratory tracts of healthy Melanesian children. The distribution of nonserotypable H. influenzae strains occurred throughout all biotypes, and the frequency of nonencapsulated biotype III and IV strains differed significantly from serotypable organisms with the same biotype (P less than 0.001).