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diode-pumped Q-switched and injection-seeded single-frequency laser, generating tunable laser radiation at 935 nm, is presented. Using Nd:YGG (YGaO) as the active medium, the laser that was developed to serve as a transmitter for water-vapor lidar measurements. The configuration consists of a stable resonator in rod geometry that is injection seeded by a narrowband diode laser and stabilized by the ramp-and-fire technique. Energy scaling was done in a power amplifier in slab geometry. Both oscillator and amplifier crystal were diode pumped at 806 nm. More than 30 mJ pulse energy at 100 Hz repetition rate with a beam propagation factor of M<1.4 and pulse duration of 52 ns in single-frequency mode were generated. To our knowledge this is the first direct generation of 935 nm Q-switched pulses from Nd:YGG suitable for water-vapor measurements. The reported results show great promise of this laser in applications where high efficiency and reduced complexity is indispensable, such as for spaceborne or airborne water-vapor lidar instruments. [ABSTRACT FROM AUTHOR]

diode-pumped, single-frequency laser system emitting at 935 nm has recently been developed to serve as the transmitter for water vapor differential absorption lidar (DIAL) measurements. This laser uses Nd:YGG (YGaO) as the active medium and emits radiation directly at 935 nm without the need of additional frequency conversion processes. The system was diode-pumped at 806 nm and was built up in a master-oscillator-power-amplifier configuration. It generates more than 30 mJ of pulse energy at 100 Hz repetition rate with a beam quality ( M) of better than 1.4. Since water vapor DIAL demands for stringent requirements of the spectral properties those were carefully investigated in the scope of this paper. Single-frequency operation is achieved by injection seeding and active length control of the oscillator cavity. The range of continuously tunable single-frequency radiation extends to ∼0.4 nm centered around 935.31 nm. Values of the spectral purity of >99.996% were determined using long-pass absorption measurements in the atmosphere exceeding the requirements by a large margin. Finally, for the first time water vapor DIAL measurements were performed using a Nd:YGG laser. The reported results show much promise of these directly pumped lasers at 935 nm for future spaceborne but also airborne water vapor lidar systems. [ABSTRACT FROM AUTHOR]

Kuru reached epidemic proportions by the mid-twentieth century among the Fore people of New Guinea and disappeared after the abolition of cannibalistic rituals. To determine susceptibility to kuru and its role in the spread and elimination of the epidemic, we analyzed the PRNP gene coding sequences in 5 kuru patients; no germline mutations were found. Analysis of the PRNP 129 methionine (M)/valine (V) polymorphism in 80 patients and 95 unaffected controls demonstrated that the kuru epidemic preferentially affected individuals with the M/M genotype. A higher representation of M/M carriers was observed among the affected young Fore males entering the age of risk, whereas a lower frequency of M/M homozygotes was found among the survivors. M/V and V/V genotypes predisposed to a lower risk of disease development and longer incubation times. These findings are relevant to the current outbreak of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom, because all vCJD patients tested thus far have been M/M carriers. [ABSTRACT FROM AUTHOR]

Antigenic polymorphism and HLA restriction may limit the immunogenicity of a subunit vaccine against liver-stage Plasmodium falciparum. We examined 59 clinical isolates and five laboratory clones of P. falciparum for polymorphism in the N- and C-terminal regions of LSA-1, evaluated binding of the corresponding peptides to selected HLA class I alleles, and measured IFN-γ responses in residents of a malaria-endemic area of Papua New Guinea where HLA-A*1101, -24, -B13, and -B40 are the most common class I alleles. LSA-1 polymorphism was limited to a single non-synonymous mutation encoding serine (S), proline (P), or threonine (T) at amino acid 85. Nine-mer 84–92 peptides with S, T, or P at the primary anchor position bound differentially to HLA-A11, -A2, and -B7. IFN-γ ELISPOT responses increased with age in malaria-exposed subjects: 14–16% and 30–36% of 2–5- and 6–54-year-olds, respectively, had ≥ 10 IFN-γ-secreting cells/106 peripheral blood mononuclear cells when stimulated with at least one peptide variant (P < 0·05). IFN-γ responses to all three peptides were also greater for older than younger individuals. No children < 3 years old had lymphocytes that responded to all three 84–92 peptides, whereas 45% of adults (mean age 48 years) had aggregated IFN-γ responses. These data support the notion that age-related cumulative exposure to P. falciparum increases the frequency of IFN-γ responses to polymorphic epitopes of liver-stage antigens such as LSA-1. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

SummaryField studies were carried out to determine the impact of mass human treatment with ivermectin on the survival of anthropophagic mosquitoes of the Anopheles punctulatus complex (Diptera: Culicidae), the vectors of lymphatic filariasis and malaria in Papua New Guinea. In a village where mass treatment had been given, using 400 μg/kg ivermectin plus 6 mg/kg diethylcarbamazine citrate (DEC), we performed pre- and post-treatment collections of freshly blood-engorged mosquitoes from the same nine bedrooms. All blood-fed mosquitoes collected less than 4 days after mass treatment died within 9 days, whereas 67% of those collected before treatment survived for > 9 days. Comparison (using the log-rank test) of the survival curves for mosquitoes collected (i) before treatment, (ii) < 4 days after treatment, and (iii) 28 days after treatment, showed the survival rate of group (ii) to be significantly lower than the other two (χ2 = 176, df = 2, P < 0.0001). Pre- and post-treatment all-night landing catches showed no reduction in human biting rates in the experimental village. In another village, where people were mass treated with ivermectin (400 μg/kg) only, the survival rates of freshly blood-engorged An.punctulatus collected from bedroom resting-sites less than 1 day after treatment, were compared to similar collections carried out at the same time in a nearby village where people were not treated with ivermectin. The 48-h survival rate for the ivermectin-treated village was 31% compared to 94% for the other; this difference was highly significant (χ2 = 32.42, df = 1, P < 0.0001). Mosquitoes fed 2 months post-treatment with DEC or collected 38 days post-treatment with ivermectin had normal survival rates. We conclude that the duration of the systemic lethal effect of ivermectin on mosquitoes is insufficient to be of epidemiological significance in filariasis control programmes that are based on biannual and annual... [ABSTRACT FROM AUTHOR]

Antibodies against pneumococcal polysaccharides were measured by ELISA in Papua New Guinean children with pneumonia aged 0-14 months, in age-matched healthy Papua New Guinean controls and in healthy expatriate children living in Papua New Guinea. At 0-5 months of age, the EgG antibody titres against six of the eight polysaccharides measured were significantly lower in pneumonia patients than in both control groups. Antibody titres in 6-14-month-old Papua New Guinean controls were significantly lower than in control Papua New Guineans aged 0-5 months for five of the eight polysaccharides tested. In the 6-14-months age group the antibody titre was significantly lower in pneumonia patients than in controls for only one polysaccharide. For seven of the eight serotypes tested, antibody levels in expatriate controls did not decline with age. Antibody responses of Papua New Guinean children aged 6-18 months to a 23-valent pneumococcal vaccine were serotype dependent. Fold increases in response to the vaccine were greatest for the IgA isotype. IgG antibody responses were greater than three fold to four of the eight serotypes tested. [ABSTRACT FROM AUTHOR]

Segregation analysis on 228 family pedigrees collected from a Papua New Guinean population provided data that strongly supported a previous report of an autosomal recessive pattern of inheritance of a susceptibility to tinea imbricata. The frequency of the susceptibility gene within the population studied was found to be 0.49 +/- 0.04, calculated on the assumption of an autosomal recessive mode of inheritance. However, in spite of the strong evidence in support of autosomal recessive inheritance, the possibility of autosomal dominant inheritance with reduced penetrance cannot be excluded. [ABSTRACT FROM PUBLISHER]

Ultrasound was used to measure newborn splenic dimensions and calculate the volumes in a malarious and a non-malarious region of Papua New Guinea. The median splenic volume of infants born in Madang, where malaria transmission is high throughout the year, was 5.2 cm3/kg, while that of infants born in Goroka, where malaria is not endemic, was 2.6 cm3/kg. The cause of this difference is unknown, but possible explanations include fetal exposure to malaria antigens in utero and the high incidence of inherited red cell disorders in the malarious regions of Papua New Guinea. [ABSTRACT FROM AUTHOR]

The results of a population survey of blood pressure in the adult residents of two highland villages in the Asaro Valley, Papua New Guinea are reported. The survey was conducted in 1983 as part of a wider epidemiological investigation of non-communicable disease in Papua New Guinea. Response to the survey was 95%, and 308 subjects were examined. Population estimates of both systolic and diastolic blood pressures were low and there was a virtual absence of hypertension, as defined by internationally recommended criteria. There was no evidence of a rise in blood pressure with age, and the association between blood pressure and indices of obesity was weak. These findings are consistent with previous studies of blood pressure in traditional Papua New Guinean societies. The two villages differed with respect to their degree of modernisation. An unexpected finding was that in both sexes, both systolic and diastolic blood pressures were higher in the more traditional village. In each case, these differences were consistent across the three age groups examined, and they could not be explained by differences between the villages with respect to the indices of obesity. Analysis of variance showed that the higher blood pressures in the more traditional village were most unlikely to be due to chance (p less than 0.001). The explanation for this finding remains obscure. [ABSTRACT FROM PUBLISHER]

In this study we have examined serum from patients with Plasmodium falciparum malaria, collected at the time of acute attack and 14 days later. We have also examined sequential samples of sera taken from children living in Madang Province, Papua New Guinea, an area endemic for malaria. The total amount of antibody directed against P. falciparum in acute phase sera was less than that found in matched controls. An in vitro assay measuring inhibition of penetration of uninfected erythrocytes by merozoites of P. falciparum revealed less inhibitory activity in acute phase sera than in matched controls. The longitudinal study of sera from village children demonstrated that non-specific inhibition of intracellular parasite growth was fairly stable, while merozoite inhibiting activity was unstable and varied with time. A cloned P. falciparum species has been used to directly demonstrate the specific growth enhancement by serum in vitro. [ABSTRACT FROM AUTHOR]

Describes presumptive viruses that have been isolated from pools made from mosquitoes collected in the Ord River area of North-West Australia. Dominant mosquito species caught in the vicinity of Kununurra; Dominance of flaviviruses.

Studies the Ord Valley of tropical Western Australia for arbovirus activity following the development of a man-made lake of considerable size, a diversion dam and an irrigation scheme. Dominance of Culex annulirostris in the mosquito fauna of the Ord Valley; Significance of Lake Argyle as an arbovirus ecosystem; Checklist of the recorded mosquito fauna of the Ord Valley.

Presents the results of hemagglutination-inhibition tests carried out on sera from persons, cattle and birds in the Kimberly area. High percentage of antibody to Murray Valley Encephalitis in humans, birds and cattle; Relation of the findings to the evolution and ecology of arboviruses in the Ord River area.

Background: No comprehensive data on the clinical features and the prognosis of cerebral malaria in the South Pacific are available at present. We conducted a prospective study in children with cerebral malaria to assess the case fatality rate (CFR) in the region and to identify potential risk factors for death.Methods: We recruited 134 children admitted to the Madang General Hospital between April 1991 and October 1993 with a strictly defined diagnosis of cerebral malaria. Besides clinical examination, we collected a blood sample for parasitological haematological and biochemical assessment.Results: The CFR was 11.9% and the prevalence of residual neurological sequelae at discharge was 1.5%. The proportion of children presenting with deep coma (12%) or hypoglycaemia (17%) was lower in our study than in African ones, where severe complications are more frequent. Also mortality associated with hypoglycaemia on admission was lower. Clinical or laboratory conditions significantly associated with death were deep coma, malarial anaemia and hyperleucocytosis.Conclusions: All conditions associated with deep coma, such as shock, hypoglycaemia and acidosis, should be corrected. Also prompt administration of blood transfusions to patients with anaemia is likely to reduce the occurrence of death in Papua New Guinean children with cerebral malaria. [ABSTRACT FROM AUTHOR]

In a study on a Caucasian population in Western Australia the prevalence of antibodies to Epstein–Barr virus (EBV) was 41% in the 9- to 10-year age group, 80% in the 16 to 19-year age group and 92% in young adults. The age-specific annual seroconversion rates indicated two peaks of primary EBV infection in the population studied – one under 5 years of age and the other at adolescence. The geometric mean titre rose with age, from 23 at 5–6 years to 53 at 36–40 years.It was shown that in 73 families studied there was evidence of probable spread of EBV infection among siblings, particularly between those of the same sex.Serological study of patients with infectious mononucleosis indicated that 100% of those examined had antibody to EBV and the geometric mean titre was elevated to 210. Rising titres and seroconversion was demonstrated in these patients together with successful establishment of EBV-carrying cell lines from the peripheral blood in two-thirds of the cases. [ABSTRACT FROM PUBLISHER]

Isolation and partial sequencing of human T-lymphotropic virus type I (HTLV-I) variants from inhabitants of Papua New Guinea (PNG) and the Solomon Islands has confirmed the existence of virus infection in Melanesian populations. To determine the geographical distribution of seropositivity to HTLV-I in PNG we have tested 2907 serum and plasma samples collected between 1972 to 1991 from 16 different population groups. Samples were screened using a particle agglutination assay and confirmed by p21e-enhanced Western immunoblot (WB). From a total of 94 screen positive samples run on WB, 56 (60%) were confirmed positive (positive for both env and gag products) and 38 (40%) were WB-indeterminate ( gag products only). The prevalence of WB-confirmed antibodies to HTLV-I in lowland and island populations ranged from 0 to 5.4%. There were no confirmed antibody positives in the highland populations surveyed. Geographically isolated populations living on the fringes of the highlands ranged in seropositivity from 0.2 to 5.8%. Two of the subjects surveyed gave WB antibody patterns characteristic of HTLV-II rather than HTLV-I infection. [ABSTRACT FROM AUTHOR]

Serum samples collected in 1984 during a malariometric survey of two villages in the East Sepik Province of Papua New Guinea were tested for antibodies to HTLV-I. None of the villagers showed any symptoms suggestive of retrovirus infection. Eighteen of the 186 (9.5%) sera tested at that time were found to be positive. Blood samples were subsequently obtained from fifteen of the eighteen positives and subjected to analysis by enzyme-linked immunosorbent assay (ELISA), radioimmuno assay (RIA), radioimmunoprecipitation assay (RIPA), and Western blot (WB). Fourteen of the fifteen gave a positive ELISA response, but none were unequivocally positive by p 24 RIA. All sera tested were reactive to gag antigens by WB, but gave 'indeterminate' results currently accepted criteria. Notably absent from the WB profiles of all of the study subjects was an antibody response to HTLV-I envelope protein gp 46. It is possible that these antibody responses are directed against a variant of HTLV-I or to a novel retrovirus which possesses core antigens similar to those of HTLV-I but has different envelope antigens. Until a virus is isolated, or the viral genome is identified in infected lymphocytes, the possibility remains that the response may be due to factors unrelated to retrovirus infection. [ABSTRACT FROM AUTHOR]