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1.
Proc Natl Acad Sci U S A ; 119(45): e2204993119, 2022 Nov 08.
Article in English | MEDLINE | ID: mdl-36322765

ABSTRACT

Community-associated, methicillin-resistant Staphylococcus aureus (MRSA) lineages have emerged in many geographically distinct regions around the world during the past 30 y. Here, we apply consistent phylodynamic methods across multiple community-associated MRSA lineages to describe and contrast their patterns of emergence and dissemination. We generated whole-genome sequencing data for the Australian sequence type (ST) ST93-MRSA-IV from remote communities in Far North Queensland and Papua New Guinea, and the Bengal Bay ST772-MRSA-V clone from metropolitan communities in Pakistan. Increases in the effective reproduction number (Re) and sustained transmission (Re > 1) coincided with spread of progenitor methicillin-susceptible S. aureus (MSSA) in remote northern Australian populations, dissemination of the ST93-MRSA-IV genotype into population centers on the Australian East Coast, and subsequent importation into the highlands of Papua New Guinea and Far North Queensland. Applying the same phylodynamic methods to existing lineage datasets, we identified common signatures of epidemic growth in the emergence and epidemiological trajectory of community-associated S. aureus lineages from America, Asia, Australasia, and Europe. Surges in Re were observed at the divergence of antibiotic-resistant strains, coinciding with their establishment in regional population centers. Epidemic growth was also observed among drug-resistant MSSA clades in Africa and northern Australia. Our data suggest that the emergence of community-associated MRSA in the late 20th century was driven by a combination of antibiotic-resistant genotypes and host epidemiology, leading to abrupt changes in lineage-wide transmission dynamics and sustained transmission in regional population centers.


Subject(s)
Community-Acquired Infections , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Humans , Staphylococcus aureus/genetics , Staphylococcal Infections/epidemiology , Australia/epidemiology , Anti-Bacterial Agents/pharmacology , Pakistan , Community-Acquired Infections/epidemiology , Microbial Sensitivity Tests
2.
J Appl Microbiol ; 2024 Jul 30.
Article in English | MEDLINE | ID: mdl-39081072

ABSTRACT

AIMS: Antibiotic resistance is a global health crisis. Roughly two-thirds of all antibiotics used are in production animals, which has the potential to impact on the development of antibiotic resistance in bacterial pathogens of humans. There is little visibility on the extent of antibiotic resistance in the Australian food chain. This study sought to establish the incidence of antibiotic resistance among enterococci from poultry in Victoria. METHODS AND RESULTS: In 2016, poultry from a Victorian processing facility were swabbed immediately post-slaughter and cultured for Enterococcus species. All isolates recovered were speciated and tested for antibiotic susceptibility to twelve antibiotics following the Clinical Laboratory Standards Institute guidelines. Six farms and 207 birds were sampled and from these 285 isolates of Enterococcus were recovered. Eight different enterococcal species were identified: E. faecalis (n = 122; 43%), E. faecium (n = 92; 32%), E. durans (n = 35; 12%), E. thailandicus (n = 23; 8%), E. hirae (n = 10; 3%) and a single each of E. avium, E. gallinarum, and E. mundtii. Reduced susceptibility to older classes of antibiotic were common, in particular: erythromycin (73%), rifampin (49%), nitrofurantoin (40%) and ciprofloxacin (39%). Two vancomycin intermediate isolates were recovered, but no resistance was detected to either linezolid or gentamicin. CONCLUSIONS: The relatively high numbers of a recently described species, E. thailandicus, suggests this species might be well adapted to colonise poultry. The incidence of antibiotic resistance is lower in isolates from poultry than in human medicine in Australia. These results suggest that poultry may serve as a reservoir for older antibiotic resistance genes but is not driving the emergence of antimicrobial resistance in human bacterial pathogens. This is supported by the absence of resistance to linezolid and gentamicin.

3.
Mol Biol Evol ; 39(3)2022 03 02.
Article in English | MEDLINE | ID: mdl-35171290

ABSTRACT

Nanopore sequencing and phylodynamic modeling have been used to reconstruct the transmission dynamics of viral epidemics, but their application to bacterial pathogens has remained challenging. Cost-effective bacterial genome sequencing and variant calling on nanopore platforms would greatly enhance surveillance and outbreak response in communities without access to sequencing infrastructure. Here, we adapt random forest models for single nucleotide polymorphism (SNP) polishing developed by Sanderson and colleagues (2020. High precision Neisseria gonorrhoeae variant and antimicrobial resistance calling from metagenomic nanopore sequencing. Genome Res. 30(9):1354-1363) to estimate divergence and effective reproduction numbers (Re) of two methicillin-resistant Staphylococcus aureus (MRSA) outbreaks from remote communities in Far North Queensland and Papua New Guinea (PNG; n = 159). Successive barcoded panels of S. aureus isolates (2 × 12 per MinION) sequenced at low coverage (>5× to 10×) provided sufficient data to accurately infer genotypes with high recall when compared with Illumina references. Random forest models achieved high resolution on ST93 outbreak sequence types (>90% accuracy and precision) and enabled phylodynamic inference of epidemiological parameters using birth-death skyline models. Our method reproduced phylogenetic topology, origin of the outbreaks, and indications of epidemic growth (Re > 1). Nextflow pipelines implement SNP polisher training, evaluation, and outbreak alignments, enabling reconstruction of within-lineage transmission dynamics for infection control of bacterial disease outbreaks on portable nanopore platforms. Our study shows that nanopore technology can be used for bacterial outbreak reconstruction at competitive costs, providing opportunities for infection control in hospitals and communities without access to sequencing infrastructure, such as in remote northern Australia and PNG.


Subject(s)
Methicillin-Resistant Staphylococcus aureus , Nanopore Sequencing , Bacteria/genetics , Disease Outbreaks , Genome, Bacterial , High-Throughput Nucleotide Sequencing , Methicillin-Resistant Staphylococcus aureus/genetics , Phylogeny , Staphylococcus aureus/genetics
4.
Appl Environ Microbiol ; 86(19)2020 09 17.
Article in English | MEDLINE | ID: mdl-32737126

ABSTRACT

Salmonella enterica serovar Hvittingfoss is an important foodborne serotype of Salmonella, being detected in many countries where surveillance is conducted. Outbreaks can occur, and there was a recent multistate foodborne outbreak in Australia. S Hvittingfoss can be found in animal populations, though a definitive animal host has not been established. Six species of birds were sampled at Roebuck Bay, a designated Ramsar site in northwestern Australia, resulting in 326 cloacal swabs for bacterial culture. Among a single flock of 63 bar-tailed godwits (Limosa lapponica menzbieri) caught at Wader Spit, Roebuck Bay, in 2018, 17 (27%) were culture positive for Salmonella All other birds were negative for Salmonella The isolates were identified as Salmonella enterica serovar Hvittingfoss. Phylogenetic analysis revealed a close relationship between isolates collected from godwits and the S Hvittingfoss strain responsible for a 2016 multistate foodborne outbreak originating from tainted cantaloupes (rock melons) in Australia. While it is not possible to determine how this strain of S Hvittingfoss was introduced into the bar-tailed godwits, these findings show that wild Australian birds are capable of carrying Salmonella strains of public health importance.IMPORTANCESalmonella is a zoonotic pathogen that causes gastroenteritis and other disease presentations in both humans and animals. Serovars of S. enterica commonly cause foodborne disease in Australia and globally. In 2016-2017, S Hvittingfoss was responsible for an outbreak that resulted in 110 clinically confirmed human cases throughout Australia. The origin of the contamination that led to the outbreak was never definitively established. Here, we identify a migratory shorebird, the bar-tailed godwit, as an animal reservoir of S Hvittingfoss. These birds were sampled in northwestern Australia during their nonbreeding period. The presence of a genetically similar S Hvittingfoss strain circulating in a wild bird population, 2 years after the 2016-2017 outbreak and ∼1,500 km from the suspected source of the outbreak, demonstrates a potentially unidentified environmental reservoir of S Hvittingfoss. While the birds cannot be implicated in the outbreak that occurred 2 years prior, this study does demonstrate the potential role for wild birds in the transmission of this important foodborne pathogen.


Subject(s)
Bird Diseases/epidemiology , Charadriiformes , Salmonella Infections, Animal/epidemiology , Salmonella enterica/isolation & purification , Animals , Bird Diseases/microbiology , Female , Incidence , Male , Prevalence , Salmonella Infections, Animal/microbiology , Serogroup , Western Australia/epidemiology
5.
Clin Infect Dis ; 68(9): 1472-1481, 2019 04 24.
Article in English | MEDLINE | ID: mdl-30184183

ABSTRACT

BACKGROUND: There are little data on the immunogenicity of PCV10 and PCV13 in the same high-risk population. METHODS: PCV10 and PCV13 were studied head-to-head in a randomized controlled trial in Papua New Guinea in which 262 infants received 3 doses of PCV10 or PCV13 at 1, 2, and 3 months of age. Serotype-specific immunoglobulin G (IgG) concentrations, and pneumococcal and nontypeable Haemophilus influenzae (NTHi) carriage were assessed prevaccination and at 4 and 9 months of age. Infants were followed up for safety until 9 months of age. RESULTS: One month after the third dose of PCV10 or PCV13, ˃80% of infants had IgG concentrations ≥0.35µg/mL for vaccine serotypes, and 6 months postvaccination IgG concentrations ≥0.35 µg/mL were maintained for 8/10 shared PCV serotypes in > 75% of children vaccinated with either PCV10 or PCV13. Children carried a total of 65 different pneumococcal serotypes (plus nonserotypeable). At 4 months of age, 92% (95% confidence interval [CI] 85-96) of children vaccinated with PCV10 and 81% (95% CI 72-88) vaccinated with PCV13 were pneumococcal carriers (P = .023), whereas no differences were seen at 9 months of age, or for NTHi carriage. Both vaccines were well tolerated and not associated with serious adverse events. CONCLUSIONS: Infant vaccination with 3 doses of PCV10 or PCV13 is safe and immunogenic in a highly endemic setting; however, to significantly reduce pneumococcal disease in these settings, PCVs with broader serotype coverage and potency to reduce pneumococcal carriage are needed. CLINICAL TRIALS REGISTRATION: NCT01619462.


Subject(s)
Haemophilus Infections/prevention & control , Immunogenicity, Vaccine , Pneumococcal Vaccines/administration & dosage , Pneumonia, Pneumococcal/prevention & control , Vaccination/methods , Antibodies, Bacterial/blood , Female , Haemophilus Infections/immunology , Haemophilus Infections/microbiology , Haemophilus influenzae/drug effects , Haemophilus influenzae/growth & development , Haemophilus influenzae/immunology , Humans , Immunoglobulin G/blood , Infant , Infant, Newborn , Male , Papua New Guinea , Patient Safety , Pneumonia, Pneumococcal/immunology , Pneumonia, Pneumococcal/microbiology , Serogroup , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/growth & development , Streptococcus pneumoniae/immunology
6.
Emerg Infect Dis ; 25(12): 2266-2269, 2019 12.
Article in English | MEDLINE | ID: mdl-31742504

ABSTRACT

We report a case of Barmah Forest virus infection in a child from Central Province, Papua New Guinea, who had no previous travel history. Genomic characterization of the virus showed divergent origin compared with viruses previously detected, supporting the hypothesis that the range of Barmah Forest virus extends beyond Australia.


Subject(s)
Alphavirus Infections/diagnosis , Alphavirus Infections/virology , Alphavirus/classification , Alphavirus/genetics , Alphavirus/isolation & purification , Alphavirus Infections/epidemiology , Alphavirus Infections/transmission , Animals , Bayes Theorem , Child, Preschool , Chlorocebus aethiops , Humans , Male , Monte Carlo Method , Papua New Guinea , Phylogeny , Vero Cells
7.
Virus Genes ; 55(6): 739-768, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31428925

ABSTRACT

Avian influenza viruses (AIVs) circulate globally, spilling over into domestic poultry and causing zoonotic infections in humans. Fortunately, AIVs are not yet capable of causing sustained human-to-human infection; however, AIVs are still a high risk as future pandemic strains, especially if they acquire further mutations that facilitate human infection and/or increase pathogenesis. Molecular characterization of sequencing data for known genetic markers associated with AIV adaptation, transmission, and antiviral resistance allows for fast, efficient assessment of AIV risk. Here we summarize and update the current knowledge on experimentally verified molecular markers involved in AIV pathogenicity, receptor binding, replicative capacity, and transmission in both poultry and mammals with a broad focus to include data available on other AIV subtypes outside of A/H5N1 and A/H7N9.


Subject(s)
Genetic Markers/genetics , Influenza in Birds/genetics , Influenza, Human/genetics , Zoonoses/genetics , Animals , Birds/genetics , Birds/virology , Drug Resistance, Viral/genetics , Humans , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza in Birds/epidemiology , Influenza in Birds/virology , Influenza, Human/virology , Pandemics , Poultry/genetics , Poultry/virology , Zoonoses/virology
8.
Emerg Infect Dis ; 24(6): 1103-1107, 2018 06.
Article in English | MEDLINE | ID: mdl-29774842

ABSTRACT

In January 2017, an estimated 3,700 (93%) of 4,000 Khaki Campbell ducks (Anas platyrhynchos domesticus) died in Kampong Thom Province, Cambodia. We detected low pathogenicity avian influenza A(H7N3) virus and anatid herpesvirus 1 (duck plague) in the affected flock; however, the exact cause of the mortality event remains unclear.


Subject(s)
Ducks/virology , Influenza A Virus, H7N3 Subtype/physiology , Poultry Diseases/epidemiology , Poultry Diseases/virology , Animals , Cambodia/epidemiology , DNA Viruses , Genes, Viral , Geography, Medical , History, 21st Century , Influenza A Virus, H7N3 Subtype/classification , Influenza A Virus, H7N3 Subtype/isolation & purification , Mortality , Phylogeny , Poultry Diseases/history , Poultry Diseases/mortality , Public Health Surveillance , Virulence
10.
J Clin Microbiol ; 53(4): 1317-23, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25673788

ABSTRACT

Sulfadoxine-pyrimethamine (SP) plus azithromycin (AZ) (SPAZ) has the potential for intermittent preventive treatment of malaria in pregnancy (IPTp), but its use could increase circulation of antibiotic-resistant bacteria associated with severe pediatric infections. We evaluated the effect of monthly SPAZ-IPTp compared to a single course of SP plus chloroquine (SPCQ) on maternal nasopharyngeal carriage and antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus at delivery among 854 women participating in a randomized controlled trial in Papua New Guinea. Serotyping was performed, and antibiotic susceptibility was evaluated by disk diffusion and Etest. Potential risk factors for carriage were examined. Nasopharyngeal carriage at delivery of S. pneumoniae (SPAZ, 7.2% [30/418], versus SPCQ, 19.3% [84/436]; P<0.001) and H. influenzae (2.9% [12/418] versus 6.0% [26/436], P=0.028), but not S. aureus, was significantly reduced among women who had received SPAZ-IPTp. The number of macrolide-resistant pneumococcal isolates was small but increased in the SPAZ group (13.3% [4/30], versus SPCQ, 2.2% [2/91]; P=0.033). The proportions of isolates with serotypes covered by the 13-valent pneumococcal conjugate vaccine were similar (SPAZ, 10.3% [3/29], versus SPCQ, 17.6% [16/91]; P=0.352). Although macrolide-resistant isolates were rare, they were more commonly detected in women who had received SPAZ-IPTp, despite the significant reduction of maternal carriage of S. pneumoniae and H. influenzae observed in this group. Future studies on SPAZ-IPTp should evaluate carriage and persistence of macrolide-resistant S. pneumoniae and other pathogenic bacteria in both mothers and infants and assess the clinical significance of their circulation.


Subject(s)
Antibiotic Prophylaxis/methods , Antimalarials/therapeutic use , Azithromycin/therapeutic use , Bacterial Infections/microbiology , Malaria/prevention & control , Nasopharynx/microbiology , Adolescent , Adult , Antibiotic Prophylaxis/adverse effects , Antimalarials/adverse effects , Azithromycin/adverse effects , Bacterial Infections/epidemiology , Carrier State/epidemiology , Carrier State/microbiology , Cross-Sectional Studies , Drug Combinations , Drug Resistance, Bacterial , Female , Haemophilus influenzae/drug effects , Haemophilus influenzae/isolation & purification , Humans , Microbial Sensitivity Tests , Papua New Guinea , Pregnancy , Pyrimethamine/adverse effects , Pyrimethamine/therapeutic use , Serotyping , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purification , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/isolation & purification , Sulfadoxine/adverse effects , Sulfadoxine/therapeutic use , Young Adult
11.
BMC Infect Dis ; 15: 485, 2015 Oct 27.
Article in English | MEDLINE | ID: mdl-26521138

ABSTRACT

BACKGROUND: Bacterial meningitis remains an important infection globally, with the greatest burden in children in low-income settings, including Papua New Guinea (PNG). We present serotype, antimicrobial susceptibility and outcome data from paediatric meningitis patients prior to introduction of Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines (PCVs) in PNG, providing a baseline for evaluation of immunisation programs. METHODS: Cerebrospinal fluid (CSF) was collected from children admitted to Goroka General Hospital with suspected meningitis between 1996 and 2005. Culture and sensitivity was conducted, and pneumococci and H. influenzae were serotyped. Laboratory findings were linked to clinical outcomes. RESULTS: We enrolled 1884 children. A recognised pathogen was identified in 375 children (19.9%). Streptococcus pneumoniae (n = 180) and Hib (n = 153) accounted for 88.8% of pathogens isolated. 24 different pneumococcal serogroups were identified; non-PCV types 2, 24 and 46 accounted for 31.6% of pneumococcal meningitis. 10- and 13-valent PCVs would cover 44.1% and 45.4% of pneumococcal meningitis respectively. Pneumococcal isolates were commonly resistant to penicillin (21.5%) and 23% of Hib isolates were simultaneously resistant to ampicillin, co-trimoxazole and chloramphenicol. The case fatality rate in patients with a recognised bacterial pathogen was 13.4% compared to 8.5% in culture-negative patients. CONCLUSIONS: If implemented in routine expanded programme of immunisation (EPI) with high coverage, current PCVs could prevent almost half of pneumococcal meningitis cases. Given the diversity of circulating serotypes in PNG serotype replacement is of concern. Ongoing surveillance is imperative to monitor the impact of vaccines. In the longer term vaccines providing broader protection against pneumococcal meningitis will be needed.


Subject(s)
Anti-Infective Agents/pharmacology , Haemophilus influenzae type b/isolation & purification , Meningitis, Bacterial/microbiology , Meningitis, Pneumococcal/microbiology , Streptococcus pneumoniae/isolation & purification , Female , Haemophilus influenzae type b/drug effects , Haemophilus influenzae type b/pathogenicity , Hospitals, General , Humans , Immunization Programs , Infant , Male , Meningitis, Bacterial/immunology , Meningitis, Bacterial/prevention & control , Meningitis, Pneumococcal/immunology , Meningitis, Pneumococcal/prevention & control , Microbial Sensitivity Tests , Papua New Guinea , Pneumococcal Vaccines/pharmacology , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/pathogenicity , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology , Vaccines, Conjugate/pharmacology
12.
Am J Phys Anthropol ; 158(3): 359-70, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26173929

ABSTRACT

OBJECTIVES: We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ(15) NHair-Diet : δ(15) NHair - δ(15) NDiet ) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ(15) N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ(15) N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ(15) N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants. MATERIALS AND METHODS: These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ(15) N was estimated by comparing hair δ(15) N values to mean dietary δ(15) N values calculated from the recorded intake of each food item and their δ(15) N values. RESULTS: The results showed that: i) there was a significant difference in Δ(15) N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2-7.3‰ for all participants); and ii) estimated Δ(15) N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9-7.6%). DISCUSSION: We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ(15) N values of the participants.


Subject(s)
Dietary Proteins , Feeding Behavior/physiology , Hair/chemistry , Nitrogen Isotopes/analysis , Adolescent , Adult , Anthropology, Physical , Child , Female , Humans , Linear Models , Male , Middle Aged , Papua New Guinea/epidemiology , Scalp/physiology , Young Adult
13.
Am J Hum Biol ; 27(3): 349-57, 2015.
Article in English | MEDLINE | ID: mdl-25367668

ABSTRACT

OBJECTIVES: The aim of this article was to develop a semi-quantitative food frequency questionnaire (FFQ) and evaluate its validity to estimate habitual protein intake, and investigate current dietary protein intakes of Papua New Guinea (PNG) Highlanders. METHODS: A 32-item FFQ was developed and tested among 135 healthy male and female volunteers. The FFQ-estimated daily total and animal protein intakes were compared with biomarkers and 3-day Weighed Food Records (WFR) by correlation analyses, Bland-Altman plot analyses and joint classification analyses. RESULTS: The FFQ-estimated total protein intake significantly correlated with urinary nitrogen in the first morning void after adjusting urinary creatinine concentration (r = 0.28, P < 0.01) and the FFQ-estimated animal protein intake significantly correlated with the hair δ(15) N (Spearman's r = 0.34, P < 0.001). The limits of agreement were ±2.39 Z-score residuals for total protein intake and ±2.19 Z-score for animal protein intake, and intra-individual differences increased as protein intake increased. The classification into the same and adjacent quartiles was 66.0% for total protein intake and 73.6% for animal protein intake. Median daily total and animal protein intake estimates from the FFQ and the 3-day WFR showed a good agreement with differences of 0.2 and 4.9 g, respectively. None of the studied communities in the PNG Highlands met the biologically required protein intake; although the community closer to an urban center showed higher protein intake than the more remote communities. CONCLUSIONS: The newly developed 32-item FFQ for PNG Highlanders is applicable for evaluation of protein intake at the individual level. Am. J. Hum. Biol. 27:349-357, 2015. © 2014 Wiley Periodicals, Inc.


Subject(s)
Diet Surveys/methods , Ethnicity , Adolescent , Adult , Age Factors , Aged , Biomarkers , Body Weights and Measures , Child , Diet Surveys/standards , Dietary Proteins/analysis , Energy Intake , Female , Hair/chemistry , Humans , Male , Middle Aged , Papua New Guinea , Reproducibility of Results , Sex Factors , Socioeconomic Factors
14.
BMC Infect Dis ; 14: 449, 2014 Aug 20.
Article in English | MEDLINE | ID: mdl-25141942

ABSTRACT

BACKGROUND: Cholera continues to be a devastating disease in many developing countries where inadequate safe water supply and poor sanitation facilitate spread. From July 2009 until late 2011 Papua New Guinea experienced the first outbreak of cholera recorded in the country, resulting in >15,500 cases and >500 deaths. METHODS: Using the national cholera database, we analysed the spatio-temporal distribution and clustering of the Papua New Guinea cholera outbreak. The Kulldorff space-time permutation scan statistic, contained in the software package SatScan v9.2 was used to describe the first 8 weeks of the outbreak in Morobe Province before cholera cases spread throughout other regions of the country. Data were aggregated at the provincial level to describe the spread of the disease to other affected provinces. RESULTS: Spatio-temporal and cluster analyses revealed that the outbreak was characterized by three distinct phases punctuated by explosive propagation of cases when the outbreak spread to a new region. The lack of road networks across most of Papua New Guinea is likely to have had a major influence on the slow spread of the disease during this outbreak. CONCLUSIONS: Identification of high risk areas and the likely mode of spread can guide government health authorities to formulate public health strategies to mitigate the spread of the disease through education campaigns, vaccination, increased surveillance in targeted areas and interventions to improve water, sanitation and hygiene.


Subject(s)
Cholera/epidemiology , Disease Outbreaks , Adolescent , Adult , Child , Child, Preschool , Cluster Analysis , Communicable Disease Control , Developing Countries , Female , Geography , Humans , Hygiene , Infant , Male , Middle Aged , Papua New Guinea/epidemiology , Public Health , Spatio-Temporal Analysis , Vaccination , Water Microbiology , Water Supply , Young Adult
15.
Vet Parasitol ; 327: 110132, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38280252

ABSTRACT

Fasciola hepatica causes liver fluke disease in production animals and humans worldwide. Faecal egg counts (FEC) are the most common diagnostic tool for the diagnosis of liver fluke disease. However, FEC has low sensitivity and is often unreliable for the detection of patent infection. In this study, loop-mediated isothermal amplification (LAMP) was optimised and evaluated for the detection of Fasciola hepatica infection, with the aim of increased sensitivity and making it suitable for on-farm application. LAMP was initially conducted under laboratory conditions, optimised to enable visual detection using calcein dye. DNA extraction based on bead-beating was developed to enable on-farm application. LAMP results were compared to FEC and polymerase chain reaction (PCR). Under laboratory conditions, LAMP was conducted using two incubation methods: a conventional PCR thermocycler and a field-deployable LAMP instrument. When compared to a 'rigorous' FEC protocol consisting of multiple counts using a comparatively large volume of faeces and with infection confirmed post-mortem, LAMP was highly sensitive and specific (using silica membrane DNA extraction sensitivity 88 %, specificity 100 %; using sieving and beat-beating DNA extraction sensitivity 98.9 %, specificity 100 %). When applied on-farm, LAMP was compared to conventional FEC, which suggested high sensitivity but low specificity (sensitivity 97 %, specificity 37.5 %). However, further analysis, comparing field LAMP results to laboratory PCR, suggested that the low specificity was likely the outcome of the inability of conventional FEC to detect all true F. hepatica positive samples. Based on the high sensitivity and specificity of LAMP compared to a 'rigorous' FEC protocol and its ability to be used in field settings, the study demonstrates the potential of LAMP for diagnosing F. hepatica infection in agriculture.


Subject(s)
Cattle Diseases , Fasciola hepatica , Fascioliasis , Sheep Diseases , Sheep , Cattle , Animals , Humans , Fasciola hepatica/genetics , Enzyme-Linked Immunosorbent Assay/veterinary , Sheep Diseases/diagnosis , Fascioliasis/diagnosis , Fascioliasis/veterinary , Feces , Cattle Diseases/diagnosis , DNA , Sensitivity and Specificity
16.
P N G Med J ; 56(3-4): 162-5, 2013.
Article in English | MEDLINE | ID: mdl-26288935

ABSTRACT

Cholera is a severe diarrhoeal illness caused by infection with the bacterium Vibrio cholerae. From July 2009 to late 2011 Papua New Guinea (PNG) experienced thefirst outbreak of cholera ever reported in this country. During this time > 15,000 cases of cholera were reported, resulting in approximately 500 deaths. The origin of this outbreak is unknown, but considering the remote location of the initial outbreak an infected international traveller is unlikely to be the source. In this paper we review the characteristics of the PNG cholera outbreak and discuss the ongoing threat of cholera to the country and the region.


Subject(s)
Cholera/epidemiology , Disease Outbreaks , Female , Humans , Male , Papua New Guinea/epidemiology , Risk Factors
17.
P N G Med J ; 56(3-4): 166-77, 2013.
Article in English | MEDLINE | ID: mdl-26288936

ABSTRACT

Sago haemolytic disease is a rare but sometimes fatal disease found primarily in the coastal regions of Papua New Guinea and among groups in which sago is a primary source of carbohydrate. It has been known since 1961 and fungi consistently have been suspected of being involved. Investigations carried out on stored sago and samples recovered from poisoning episodes have failed to indicate the consistent presence of mycotoxins. However, fungi (especially Aspergillus, Fusarium, Penicillium, Trichoderma) with strong haemolytic activity have been associated with sago, particularly when stored in open-weave baskets and sago-leaf-wrapped bundles. The haemolytic activity has been attributed to fatty acids (principally oleic, palmitic, linoleic) contained primarily in the fungal hyphae. It is hypothesized that when these acids are released through hyphal breakdown during digestion and are present in individuals with a low serum albumin level, free fatty acid excess occurs resulting in red cell membrane destruction and intravascular haemolysis. In extreme cases, blood transfusion is required. Methods of storage providing high levels of access to oxygen favour the development of fungi: eg, leaf-encased bundles and open-weave storage favour growth over that seen in starch stored under water, such as in earthen vessels. Ensuring storage does not exceed 3-4 weeks, encouraging anaerobic conditions of the starch and maintaining protein nutrition in communities where sago is relied upon should alleviate outbreak episodes.


Subject(s)
Anemia, Hemolytic/epidemiology , Anemia, Hemolytic/microbiology , Cycas , Dietary Carbohydrates/poisoning , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Mycotoxicosis/epidemiology , Mycotoxicosis/microbiology , Food Handling , Humans , Papua New Guinea/epidemiology
18.
P N G Med J ; 56(3-4): 126-35, 2013.
Article in English | MEDLINE | ID: mdl-26288930

ABSTRACT

Water, sanitation and hygiene (WASH) interventions aim to improve health outcomes through provision of safe water supplies and improved sanitation facilities, while also promoting better hygiene practices in communities. Population Services International introduced a WASH intervention project in the Hiri District, Central Province in May 2012. Shortly after its introduction we conducted a survey to determine the uptake of the intervention and gauge its impact. We invited 400 households to participate in the study, which consisted of a questionnaire for the head of the household. A total of 395 questionnaires were completed: 314 from households that had participated in the WASH intervention and 81 that had not (controls). Results demonstrated that improved water sources were not routinely used, with a high dependence on well and surface water. While self-reported handwashing was common, use of soap was not common. Treatment of water inside the house was common in the intervention group (95%), compared to 49% in the non-WASH group. The study indicates that people in the Hiri District are supportive of a WASH intervention, with good uptake of some aspects of the intervention. The sustainability of the intervention remains unknown. Targetted interventions focusing on community priorities might be beneficial in the future.


Subject(s)
Gastrointestinal Diseases/prevention & control , Hand Disinfection , Hygiene , Public Health , Water Supply , Cross-Sectional Studies , Female , Gastrointestinal Diseases/epidemiology , Health Knowledge, Attitudes, Practice , Humans , Male , Papua New Guinea , Population Surveillance , Program Evaluation , Sanitation
19.
P N G Med J ; 56(3-4): 110-5, 2013.
Article in English | MEDLINE | ID: mdl-26288927

ABSTRACT

When cholera was first detected in Papua New Guinea (PNG) in mid-2009, national diagnostic capacity faced many challenges. This was in part due to the non-endemic status of the outbreak, resulting in few local staff experienced in Vibrio cholerae detection and poor access to the required consumables. The PNG Institute of Medical Research conducted culture on specimens from suspected cholera patients in Madang Province, with presumptive V. cholerae isolates sent to Goroka for confirmation. Of 98 samples analysed 15 were culture positive, with V. cholerae detected by polymerase chain reaction (PCR) in an additional 3 samples. Further analyses were conducted to identify other pathogenic bacteria from thiosulphate citrate bile salt sucrose (TCBS) agar. Molecular-based assays detected enteropathogenic (n = 1) and enterotoxigenic (n = 1) strains of Escherichia coli. No other major enteric pathogens were detected. The low detection rate of V. cholerae at the provincial level reflects challenges in the laboratory diagnosis of cholera and in-country challenges in responding to an outbreak of a non-endemic disease, such as lack of in-country diagnostic expertise and available consumables in the early stages. It also suggests that full aetiological investigations are warranted in future outbreaks of acute watery diarrhoea in PNG to fully elucidate the potentially complex aetiology, which could in turn guide diagnostic, treatment and prevention measures.


Subject(s)
Cholera/epidemiology , Cholera/microbiology , Disease Outbreaks , Vibrio cholerae/isolation & purification , Enterobacteriaceae/isolation & purification , Feces/microbiology , Humans , Immunoassay , Papua New Guinea/epidemiology , Polymerase Chain Reaction
20.
P N G Med J ; 56(3-4): 141-4, 2013.
Article in English | MEDLINE | ID: mdl-26288932

ABSTRACT

We evaluated the IP-Triple I immunochromatographic rapid test for the detection of rotavirus, norovirus and adenovirus using stool samples from children with diarrhoea. The detection of norovirus and adenovirus was poor compared to polymerase chain reaction assays. However, high sensitivity (92%) and specificity (99%) were obtained for the detection of rotavirus.


Subject(s)
Adenoviridae/isolation & purification , Child, Hospitalized , Chromatography, Affinity/methods , Diarrhea/virology , Norovirus/isolation & purification , Rotavirus/isolation & purification , Child, Preschool , Disease Outbreaks , Feces/virology , Female , Humans , Infant , Infant, Newborn , Male , Polymerase Chain Reaction , Sensitivity and Specificity
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