Alexander Rosewell

Clonal Origins of Vibrio cholerae O1 El Tor Strains, Papua New Guinea, 2009-2011

We used multilocus sequence typing and variable number tandem repeat analysis to determine the clonal origins of Vibrio cholerae O1 El Tor strains from an outbreak of cholera that began in 2009 in Papua New Guinea. The epidemic is ongoing, and transmission risk is elevated within the Pacific region.

Incompletely matched influenza vaccine still provides protection in frail elderly

A cluster-randomised controlled trial of antiviral treatment to control influenza outbreaks in aged-care facilities (ACFs) provided an opportunity to assess VE in the frail, institutionalised elderly. Data were pooled from five influenza outbreaks in 2007. Rapid testing methods for influenza were used to confirm outbreaks and/or identify further cases. Vaccination coverage among ACF residents ranged from 59% to 100%, whereas it was consistently low in staff (11-33%). The attack rates for laboratory-confirmed influenza in residents ranged from 9% to 24%, with the predominate strain determined to be influenza A. Sequencing of the hemagglutinin gene from a sub-sample demonstrated an incomplete match with the 2007 southern hemisphere influenza vaccine. Influenza VE was estimated to be 61% (95%CI 6%, 84%) against laboratory-confirmed influenza, 51% (95%CI -16%, 79%) against influenza-like illness, 82% (95%CI 27%, 96%) against pneumonia-related and influenza-related hospitalisations and 71% (95%CI -28%, 95%) against death from all causes. This supports the continued policy of targeted vaccination of the institutionalised, frail elderly. There is also reassurance that influenza vaccine can be effective against disease and severe outcomes, despite an incomplete vaccine match. This benefit is additional to protection from antivirals.

First reported outbreak of locally acquired hepatitis E virus infection in Australia

Objective: To determine the source and extent of a locally acquired hepatitis E virus (HEV) infection outbreak.

Sustained outbreak of measles in New South Wales, 2012: risks for measles elimination in Australia

OBJECTIVE On 7 April 2012, a recently returned traveller from Thailand to Australia was confirmed to have measles. An outbreak of measles subsequently occurred in the state of New South Wales, prompting a sustained and coordinated response by public health authorities. The last confirmed case presented on 29 November 2012. This report describes the outbreak and its characteristics. METHODS Cases were investigated following Australian protocols, including case interviews and assessment of contacts for post-exposure prophylaxis. RESULTS Of the 168 cases identified, most occurred in south-western and western Sydney (92.9%, n = 156). Notable features of this outbreak were the disproportionately high number of cases in the 10-19-year-old age group (29.2%, n = 49), the overrepresentation among people of Pacific Islander descent (21.4%, n = 36) and acquisition in health-care facilities (21.4%, n = 36). There were no reported cases of encephalitis and no deaths. DISCUSSION This was the largest outbreak of measles in Australia since 1997. Its occurrence highlights the need to maintain vigilant surveillance systems for early detection and containment of measles cases and to maintain high population immunity to measles through routine childhood immunization. Vaccination campaigns targeting susceptible groups may also be necessary to sustain Australias measles elimination status.

Mobile phone-based syndromic surveillance system, Papua New Guinea

The health care system in Papua New Guinea is fragile, and surveillance systems infrequently meet international standards. To strengthen outbreak identification, health authorities piloted a mobile phone–based syndromic surveillance system and used established frameworks to evaluate whether the system was meeting objectives. Stakeholder experience was investigated by using standardized questionnaires and focus groups. Nine sites reported data that included 7 outbreaks and 92 cases of acute watery diarrhea. The new system was more timely (2.4 vs. 84 days), complete (70% vs. 40%), and sensitive (95% vs. 26%) than existing systems. The system was simple, stable, useful, and acceptable; however, feedback and subnational involvement were weak. A simple syndromic surveillance system implemented in a fragile state enabled more timely, complete, and sensitive data reporting for disease risk assessment. Feedback and provincial involvement require improvement. Use of mobile phone technology might improve the timeliness and efficiency of public health surveillance.

Vibrio cholerae O1 in 2 Coastal Villages, Papua New Guinea

To the Editor: Cholera outbreak reports are of international public health interest, especially in areas that were previously cholera free (1). Although many recent cholera outbreaks have originated in coastal areas (2), identifying the source of cholera introduction has been challenging (1). The detection of Vibrio cholerae in coastal, brackish and riverine waters in cholera-endemic and cholera-free areas supports the view that autochtonous V. cholerae is involved in the introduction of cholera (3,4). To our knowledge, cholera has not been reported in Papua New Guinea, despite social and environmental conditions likely to facilitate transmission and the nations close proximity to cholera-endemic countries (5,6). On August 6, 2009, a physician who visited the coastal village of Lambutina reported an outbreak of acute watery diarrhea that was associated with the death of his father and 4 other persons from this and a neighboring village. The outbreak began in the village of Nambariwa and spread to neighboring Lambutina, Morobe Province. From August 13, multidisciplinary teams worked with the community to reduce the number of deaths through early identification and treatment of case-patients. The teams also worked to limit transmission through improvements to the water and sanitation infrastructure and by encouraging better hygiene practices among the villagers. A suspected case of cholera was defined as acute watery diarrhea or vomiting in a resident of Lambutina or Nambariwa villages since July 22, 2009. In the 2 villages, 77 cases were identified; attack rates were 14% in Lambutina (48/343) and 5.5% in Nambariwa (29/532). The overall case-fatality ratio was 6.5% (5/77); 2 patients died after they were discharged from the referral hospital. A retrospective frequency-matched case–control study was conducted in Lambutina to identify the risk factors associated with suspected cholera. Neighborhood controls (± 5 years of age) were selected from unaffected households. Univariate and multivariate analyses were conducted with STATA version 10 (StataCorp., College Station, TX, USA). Of the 48 case-patients in Lambutina, 43 participated in the study with 43 age-matched controls. In addition to having close contact with patients who had cholera, univariate analysis showed that case-patients were more likely to have had several exposures related to the death of other patients (Table). However, having close contact with a patient was the only independent risk factor (adjusted odds ratio 4.8, 95% confidence interval 1.7–13.4) (Table). Close contact included providing nursing care for patients or carrying patients onto boats for transport to health care facilities. From the 10 collected samples, 4 isolates were confirmed as V. cholerae O1, biotype El Tor, serotype Ogawa, by PCR detection of an O1-specific region of the rfb gene using established methods and PCR amplification of the tcpA gene polymorphism specific for the El Tor biotype (7). The ctxAB, vct genes (present in toxigenic strains) and the hemolysin gene hlyA (present in all V. cholerae strains) were detected by PCR in all 4 isolates. Although health authorities promptly identified and responded to the outbreak, they could not determine its origin. The El Nino weather phenomenon generates increased rainfall and elevated sea surface temperatures and is a predictor of cholera outbreaks (8), which puts more coastal areas at risk for such outbreaks (9). During this outbreak, Papua New Guinea reported above-average rainfall (10) and warmer sea surface temperatures. Although cholera may have been introduced to Papua New Guinea through an infectious traveler or by other means, climatic factors may have initiated plankton blooms, the abundance of which have also been associated with increased presence of V. cholerae O1. Sea and estuarine waters of these villages are plausible sources of introduction. In Lambutina, the age-specific attack rates were lowest among young children and increased among persons of middle age and among the elderly. Those providing patient care and lifting during transportation as well as those washing the bodies of the deceased may have been more represented in the >40 years age group; however, this situation may not explain the high attack rates among the elderly. Generally, after a cholera outbreak is detected, interventions aim to reduce the proportion of deaths to <1%. The overall case-fatality ratio in the outbreak discussed here was 6.5%, which reflects the challenges to accessing adequate health care in remote settings. This difficulty is exacerbated when the disease occurs for the first time because cholera awareness and preparedness will be weak, as can be seen in the early management of cases during this outbreak. Villagers who have close contact with cholera patients are at greater risk for disease and should be a focus of interventions to limit transmission (e.g., eliminating ingestion of contaminated water, improving hygiene and sanitation). Education to increase awareness of the disease and enhanced access to low-osmolarity oral rehydration solution, Hartmann solution, and zinc supplements are essential. Cholera-endemic and cholera–nonendemic countries with coastal populations are at an increasing risk for cholera outbreaks. Adequate preparation by the health care system is vital to avoid excess deaths. Table Univariate and multivariate analysis of risk factors associated with suspected cholera in Lambutina village, Papua New Guinea, 2009*

Treating and Preventing Influenza in Aged Care Facilities: A Cluster Randomised Controlled Trial

Background Influenza is an important cause of morbidity and mortality for frail older people. Whilst the antiviral drug oseltamivir (a neuraminidase inhibitor) is approved for treatment and prophylaxis of influenza during outbreaks, there have been no trials comparing treatment only (T) versus treatment and prophylaxis (T&P) in Aged Care Facilities (ACFs). Our objective was to compare a policy of T versus T&P for influenza outbreaks in ACFs. Methods and Findings We performed a cluster randomised controlled trial in 16 ACFs, that followed a policy of either “T”—oseltamivir treatment (75 mg twice a day for 5 days)—or “T&P”—treatment and prophylaxis (75 mg once a day for 10 days) for influenza outbreaks over three years, in addition to enhanced surveillance. The primary outcome measure was the attack rate of influenza. Secondary outcomes measures were deaths, hospitalisation, pneumonia and adverse events. Laboratory testing was performed to identify the viral cause of influenza-like illness (ILI) outbreaks. The study period 30 June 2006 to 23 December 2008 included three southern hemisphere winters. During that time, influenza was confirmed as the cause of nine of the 23 ILI outbreaks that occurred amongst the 16 ACFs. The policy of T&P resulted in a significant reduction in the influenza attack rate amongst residents: 93/255 (36%) in residents in T facilities versus 91/397 (23%) in T&P facilities (p = 0.002). We observed a non-significant reduction in staff: 46/216 (21%) in T facilities versus 47/350 (13%) in T&P facilities (p = 0.5). There was a significant reduction in mean duration of outbreaks (T = 24 days, T&P = 11 days, p = 0.04). Deaths, hospitalisations and pneumonia were non-significantly reduced in the T&P allocated facilities. Drug adverse events were common but tolerated. Conclusion Our trial lacked power but these results provide some support for a policy of “treatment and prophylaxis” with oseltamivir in controlling influenza outbreaks in ACFs. Trail Registration Australian Clinical Trials Registry ACTRN12606000278538

Cholera risk factors, Papua New Guinea, 2010

BackgroundCholera is newly emergent in Papua New Guinea but may soon become endemic. Identifying the risk factors for cholera provides evidence for targeted prevention and control measures.MethodsWe conducted a hospital-based case–control study to identify cholera risk factors. Using stool culture as the standard, we evaluated a cholera point of care test in the field.Results176 participants were recruited: 54 cases and 122 controls. Independent risk factors for cholera were: being over 20 years of age (aOR 2.5; 95%CI 1.1, 5.4), defecating in the open air (or river) (aOR 4.5; 95% CI 1.4, 14.4) and knowing someone who travelled to a cholera affected area (aOR 4.1; 95%CI 1.6, 10.7); while the availability of soap for handwashing at home was protective (aOR 0.41; 95%CI 0.19, 0.87). Those reporting access to a piped water distribution system in the home were twice as likely to report the availability of soap for handwashing. The sensitivity and specificity of the rapid test were 72% (95% CI 47–90) and 71% (95%CI 44–90%).ConclusionsImproving population access to the piped water distribution system and sanitation will likely reduce transmission by enabling enhanced hygiene and limiting the contamination of water sources. The One step V. cholerae O1/O139 Antigen Test is of limited utility for clinical decision making in a hospital setting with access to traditional laboratory methods. Settlement dwellers and mobile populations of all age groups should be targeted for interventions in Papua New Guinea.

Shigella spp. Antimicrobial Drug Resistance, Papua New Guinea, 2000–2009

To the Editor: Approximately half the Shigella spp. infections in developing countries are caused by endemic shigellae (1), which in these countries are responsible for ≈10% of all episodes of diarrhea among children <5 years of age and up to 75% of deaths from diarrhea (2). Deaths from epidemic Shigella spp. in the community are estimated to outnumber deaths within the healthcare setting. In Papua New Guinea, diarrhea is a major cause of hospital admission and death (3); Shigella spp. are among the most common causes of enteric bacterial infection (4,5), and S. flexneri is the most common serotype (3,6). Outbreaks of bloody diarrhea are frequently reported; however, diagnosis in remote settings is challenging, partly because the storage requirements for the organism are difficult to meet. Multidrug resistance of shigellae is not new (1); many countries have reported resistance to amoxicillin, co-trimoxazole, and chloramphenicol. For this reason, the World Health Organization recommends that all patients with bloody diarrhea be treated with either ciprofloxacin or 1 of the 3 second-line drugs: pivmecillinam, azithromycin, and ceftriaxone (7). The antimicrobial drug currently recommended for patients with bloody diarrhea in primary healthcare settings in Papua New Guinea is co-trimoxazole (8); ciprofloxacin is available only in hospitals. In August 2009, an epidemic of multidrug-resistant S. flexneri infection associated with widespread illness and death across 4 provinces of Papua New Guinea was reported to health authorities. To understand the trends and to inform antimicrobial drug policy makers, we reviewed retrospective microbiological data for 2000–2009. With the exception of 3 isolates collected during an outbreak in the border regions of the 4 provinces during 2009 (excluded from analysis), all isolates in our study were obtained as part of routine surveillance. Fecal samples were collected by clinicians from any patient seeking care for severe diarrhea at Port Moresby General Hospital. Before serologic testing was conducted, samples were spread directly on desoxycholate citrate agar and MacConkey agar plates for culture. Antimicrobial drug resistance testing was performed by using the Kirby-Bauer method. From a total of 3,419 fecal samples cultured, 136 (4.0%) were positive for Shigella spp. The most commonly isolated species was S. flexneri (90.4%); less frequently isolated were S. boydii (3.7 %), S. dysenteriae (2.9%), and S. sonnei (1.5%). Of the 123 S. flexneri isolates, 20 (16%) were further characterized; the most frequent serovars were serovar 2 (40%) and serovar 3 (30%). Many (48%) Shigella spp.–positive isolates were from children <5 years of age. The highest rates of antimicrobial drug resistance of all Shigella spp. were to amoxicillin (96%), co-trimoxazole (86%), and chloramphenicol (60%); no resistance to ciprofloxacin and cephalexin was found (Table). Table Antimicrobial drug resistance of Shigella spp., Papua New Guinea, 2000–2009* Current evidence supports the use of ciprofloxacin, ceftriaxone, and pivmecillinam for treatment of bloody diarrhea (9). It also suggests that dysentery rarely relapses if an infected child has received a full course of treatment with 1 of these drugs and the causative pathogen is sensitive to the drug. Reducing the risk for relapse of bacterial infections among children is beneficial because it reduces the likelihood of subsequent episodes of dysentery occurring in that child and of transmission to others (9). In our study, most isolates were resistant to co-trimoxazole and the other available antimicrobial drugs, indicating that their use would not have reduced illness and subsequent transmission in this setting. The lack of resistance to ciprofloxacin and cephalexin indicates that these drugs may be more effective; however, they are neither available at the primary healthcare level nor recommended in Papua New Guinea, which is cause for concern. Surveillance for antimicrobial drug resistance is essential for the containment of antimicrobial drug resistance globally. However, international surveillance depends on strong national surveillance systems. Despite the existence of a network of subnational laboratories where fecal sample cultures had been performed, these laboratories no longer perform these cultures. In 1964, the laboratory in 1 provincial hospital analyzed and subtyped 1,000 stool samples over a 15-month period (6). In our study, conducted at the national referral hospital (which limits the representativeness), we analyzed 3,419 fecal samples over a 10-year period. Outbreaks of bloody diarrhea are common in remote settings in Papua New Guinea, yet with the exception of the 3 isolates from 2009 that were excluded from analysis, no Shigella spp.–positive samples have been identified during outbreaks. Molecular methods may serve as an adjunct to traditional laboratory methods by improving sensitivity and also enabling diagnosis of Shigella spp. outbreaks among remote populations where specimen storage and transport requirements may be challenging (10). We describe extremely high rates of resistance of Shigella spp. to co-trimoxazole, the recommended treatment for bloody diarrhea in Papua New Guinea. Strengthening national surveillance for antimicrobial drug resistance would provide the evidence to better inform policy decision makers. A review of the national antimicrobial drug policy for management of bloody diarrhea is urgently needed.

Surveillance for outbreaks of influenza-like illness in the institutionalized elderly

Respiratory outbreaks are common in aged-care facilities (ACFs), are both underreported and frequently identified late, and are often associated with considerable burden of illness and death. There is emerging evidence that active surveillance coupled with early and systematic intervention can reduce this burden. Active surveillance for influenza-like illness and rapid diagnosis of influenza were established in 16 ACFs in Sydney, Australia, prior to the winter of 2006. A point-of-care influenza test and laboratory direct immunofluorescence tests for common respiratory viruses were used for diagnosis. We achieved early identification of seven respiratory disease outbreaks, two of which were caused by influenza. For the influenza outbreaks, antiviral treatment and prophylaxis were initiated 4-6 days from symptom onset in the primary case. A simple active surveillance system for influenza was successfully implemented and resulted in early detection of influenza and other respiratory disease outbreaks. This enabled earlier implementation of prevention and control measures and increased the potential effectiveness of anti-influenza chemoprophylaxis.