Epidemiology and associated risk factors of giardiasis in a peri-urban setting in New South Wales Australia.

Giardiasis is one of the most important non-viral causes of human diarrhoea. Yet, little is known about the epidemiology of giardiasis in the context of developed countries such as Australia and there is a limited information about local sources of exposure to inform prevention strategies in New South Wales. This study aimed to (1) describe the epidemiology of giardiasis and (2) identify potential modifiable risk factors associated with giardiasis that are unique to south-western Sydney, Australia. A 1:2 matched case-control study of 190 confirmed giardiasis cases notified to the South-Western Local Health District Public Health Unit from January to December 2016 was employed to investigate the risk factors for giardiasis. Two groups of controls were selected to increase response rate; Pertussis cases and neighbourhood (NBH) controls. A matched analysis was carried out for both control groups separately. Variables with a significant odds ratio (OR) in the univariate analysis were placed into a multivariable regression for each matched group, respectively. In the regression model with the NBH controls, age and sex were controlled as potential confounders. Identified risk factors included being under 5 years of age (aOR = 7.08; 95% confidence intervals (CI) 1.02-49.36), having a household member diagnosed with a gastrointestinal illness (aOR = 15.89; 95% CI 1.53-164.60) and having contact with farm animals, domestic animals or wildlife (aOR = 3.03; 95% CI 1.08-8.54). Cases that travelled overseas were at increased risk of infection (aOR = 19.89; 95% CI 2.00-197.37) when compared with Pertussis cases. This study provides an update on the epidemiology and associated risk factors of a neglected tropical disease, which can inform enhanced surveillance and prevention strategies in the developed metropolitan areas.

An outbreak of Salmonella Infantis gastroenteritis in a residential aged care facility associated with thickened fluids.

Twenty-two confirmed cases of Salmonella Infantis were identified in 70 residents of high-level care areas of a residential aged care facility in Sydney in April 2010 during an outbreak of gastroenteritis. A retrospective cohort study was conducted to identify a possible cause. Consuming a soft diet, puréed diet, or thickened fluid were each independently associated with illness. A logistic regression showed consumption of thickened fluid to be the only significant exposure associated with illness (adjusted odds ratio 11·8, 95% confidence interval 1·9-75·9). It was postulated that the thickened fluid had been contaminated by chicken mince, a sample of which also cultured S. Infantis. This finding reinforces the need to educate food-handlers on the risk of potential cross-contamination; it also highlights the need to consider all dietary components, such as thickened fluids, as potential vehicles for transmission in an outbreak.

Herpes zoster in Australia: evidence of increase in incidence in adults attributable to varicella immunization?

Rates of herpes zoster (HZ) hospitalizations, antiviral prescriptions, and New South Wales emergency-department presentations for age groups <20, 20-39, 40-59 and ⩾60 years were investigated. Trends were analysed using Poisson regression to determine if rates increased following funding of varicella immunization in Australia in November 2005. The regression analysis revealed significantly increasing trends of between 2% and 6% per year in both antiviral prescriptions and emergency-department presentations in all except the <20 years age group. When considered together, the differential changes in rates observed by age group provides preliminary evidence to indicate that HZ incidence is increasing in adults aged >20 years. However, it is not possible to attribute the increasing trends in HZ observed directly to the varicella immunization programme, and continued monitoring and analyses of data for a longer duration, both pre- and post-vaccine introduction, is required.

The interpretation of nucleic acid amplification tests for tuberculosis: do rapid tests change treatment decisions?

OBJECTIVES: To describe changes in treatment decisions after receipt of nucleic acid amplification (NAA) test for the diagnosis of M. tuberculosis. METHODS: Retrospective notes review of treatment decisions in patients receiving a NAA test for suspected pulmonary or non-pulmonary tuberculosis at the Royal Free Hospital in London between March 2001 and February 2002. Notes were sought on a 50% random sample of patients with both smear and NAA negative specimens and all patients with other specimen results. RESULTS: Two hundred and fifty patients were tested with NAA; clinical details were obtained on 138; 61 were ever treated. Seventeen (17/18) smear-negative patients were started on treatment after a positive NAA; none of six smear-negative patients treated prior to a negative NAA result had treatment stopped. Seventeen (17/21) smear-positive patients were treated prior to NAA result and all were NAA positive; treatment was delayed in four smear-positive patients until receipt of an NAA and one NAA-negative patient was not treated. CONCLUSIONS: In routine practice a positive test in an untreated smear-negative patient leads to decision to treat in almost all, but the proportion testing positive is low (8% or 17/219). In patients already on treatment negative tests did not lead to decisions to stop.

Women who decline antenatal screening for HIV infection in the era of universal testing: results of an audit of uptake in three London hospitals.

Universal screening for HIV in early pregnancy is strongly promoted policy in the United Kingdom with a target of 90 per cent uptake. We identified characteristics of women declining screening by conducting an audit at three hospitals in inner north London. In early 2002 midwives were asked to complete an audit form following first antenatal appointment. Of 2,710 women attending 401 (15 per cent) declined an HIV test. Of women who declined 38 per cent reported they had been tested for HIV in the past; 65 per cent accepted every other antenatal test. In multivariable analysis parity (OR: 1.19; 95 per cent CI 1.10-1.29 per additional child), declining other tests (OR: 3.10; 95 per cent CI 2.44-3.93 per test declined) and previous HIV testing (OR: 1.70; 95 per cent CI 1.30-2.23) were predictors of declining an HIV test. Women declining screening were not obviously from high-risk demographic groups: women from sub-Saharan Africa were not at greater risk of declining an HIV test than women from other regions.

The community prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in older people living in their own homes: implications for treatment, screening and surveillance in the UK.

Methicillin-resistant Staphylococcus aureus (MRSA) predominantly affects those over 65 years old. There may be a substantial pool of older people with MRSA in the community. We studied the prevalence in one London general practice, screening 258 older people living in their own home. MRSA (E-MRSA 15) was found in two participants (0.78%). Past history of MRSA was the only significant risk factor. The results of this and other studies suggest that national guidelines recommending early discharge for MRSA carriers have not resulted in widespread community acquisition amongst elderly people living in their own home. Community antibiotic policies for skin and soft-tissue infection do not require amendment. Patients with previous MRSA should be isolated and screened on admission especially to high-risk units.

Reasons for low reported treatment success in notified tuberculosis patients from a London hospital according to new outcome reporting.

In January 2002 the Communicable Disease Surveillance Centre (CDSC) introduced outcome reporting for tuberculosis 12 months after start of treatment. To determine whether outcome could change with longer and more detailed follow up, we examined this at 12 months and two years for a cohort notified in 2000 at a central London hospital. At 12 months 61/94 (65%) notified patients had completed treatment, 10 (16%) had died, 11 (12%) were lost to follow up, six (6%) were transferred to another service in the UK, four (4%) were still on treatment, and treatment for one (1%) patient had been stopped. After a mean follow up of two years, 65 (69%) had completed treatment. In this London service with a high prevalence of HIV infection (at least 23%), low treatment success was due to deaths, transfers and losses to follow up. The last of these was often due to patients returning to their country of origin (7 of 11). Tuberculosis was the primary or contributing cause of death in at least 4/94 (4%) cases. Completion rates need to be interpreted with caution particularly in specialist units with highly mobile populations. This has implications for national targets as well as for models of care.

Explaining risk factors for drug-resistant tuberculosis in England and Wales: contribution of primary and secondary drug resistance.

Drug-resistant tuberculosis can be transmitted (primary) or develop during the course of treatment (secondary). We investigated risk factors for each type of resistance. We compared all patients in England and Wales with isoniazid- and multidrug-resistant tuberculosis in two time-periods (1993-1994 and 1998-2000) with patients with fully sensitive tuberculosis, examining separately patients without and with previous tuberculosis (a proxy for primary and secondary drug-resistant tuberculosis). Patients with previous tuberculosis smear positivity and arrival in the United Kingdom <5 years were strongly associated with multidrug resistance and isoniazid resistance. In patients with no previous tuberculosis HIV infection, residence in London and foreign birth were risk factors for multidrug resistance, and non-white ethnicity, residence in London and HIV infection for isoniazid resistance. Risk factors for each type of resistance differ. Elevated risks associated with London residence, HIV positivity, and ethnicity were mainly seen in those without previous tuberculosis (presumed transmission).

Abattoir-associated Q fever: a Q fever outbreak during a Q fever vaccination program.

OBJECTIVES: To investigate an abattoir outbreak of Q fever in southem New South Wales with reference to the protective effect and safety of the formalin-inactivated Q fever vaccine (Q Vax) administered before and during the outbreak. METHODS: In September 1998, after notification of four Q fever cases in the abattoir, a cohort investigation of 103 workers was undertaken. Data on age, sex, immune status, vaccination status and main work area were obtained from the medical officer administering the vaccination program and abattoir records. Symptoms and occupational risk factors for illness were obtained from interview of 63 (61%) employees. RESULTS: Of 103 abattoir employees, 16 (16%) had immunity from previous Q fever exposure and 19 (18 %) had been vaccinated at least six weeks before the first case of Q fever exposure in the abattoir. Of the remaining 68 workers who were susceptible to primary infection, 29 (43%) had laboratory confirmed acute primary Q fever and eight were suspected cases. No workers vaccinated before the likely period of exposure developed Q fever. Of 32 workers vaccinated post-exposure, four developed laboratory-confirmed Q fever within eight days of vaccination. Vaccination administered 10 or more days after the likely period of exposure showed no significant protective effect (RR=0.57; 95% CI 0.13-2.57; p=0.60). CONCLUSIONS: Q-Vax was highly effective when administered in advance of the likely period of Q fever exposure. Post exposure vaccination was not shown to be protective. IMPLICATIONS: This study reinforces meat industry vaccination guidelines for abattoir employees. The optimal time to vaccinate workers is before they are put at occupational risk.

The Australian Childhood Immunisation Register: validation of the immunisation status of children who are very overdue.

OBJECTIVES: To determine the true immunisation status of children identified by the Australian Childhood Immunisation Register (ACIR) as 90 days overdue, and determine why appropriately immunised children were flagged as overdue. METHODS: A telephone survey of immunisation providers and/or parents of a stratified random sample of 850 NSW children born on or after 1 January 1996 and identified by the ACIR as 90 days overdue for at least one scheduled immunisation at 17 June 1997. The survey was conducted in June to September 1997. RESULTS: Children in the sample ranged in age from 5 to 17 months. Only 526 (61.9%) could be traced. Of these, 452 (86.6%) were fully immunised, and 75% of immunisations were given on time (within 30 days of falling due). The overall proportion of NSW children identified by ACIR as 90 days overdue who were fully immunised was an estimated 85% (95% CI 82.6%-87.4%). For the 452 fully immunised children, a reason for the child's immunisation not appearing on the register could be attributed for only 248/452 (54.8%). There was evidence that the provider had failed to submit an encounter form for 141 of these children. CONCLUSIONS: In mid-1997, more than half the children identified by ACIR as 'overdue' were fully immunised. A significant reason for fully immunised continuing to be flagged as overdue was failure to return encounter forms. IMPLICATIONS: At the time of survey the ACIR could not accurately identify unimmunised children and was of limited use as a tool for public health services to follow up very overdue children.

Hepatitis A in New South Wales, Australia from consumption of oysters: the first reported outbreak.

Between 22 January and 4 April 1997, 467 hepatitis A cases were reported to the New South Wales Health Department, Australia. To identify the cause of the outbreak, we conducted a matched case-control study, and an environmental investigation. Among 66 cases and 66 postcode-matched controls, there was a strong association between illness and consumption of oysters (adjusted odds ratio 42; 95 % confidence interval 5-379). More than two-thirds of cases reported eating oysters, including one third of cases and no controls who reported eating oysters in the Wallis Lake area. A public warning was issued on 14 February, and Wallis Lake oysters were withdrawn from sale. Hepatitis A virus was subsequently identified in oyster samples taken from the lake. Hepatitis A virus poses a special risk to consumers who eat raw oysters because it can survive for long periods in estuaries and cause severe disease.

Amoxycillin plus probenecid versus doxycycline for treatment of erythema migrans borreliosis.

72 adults with erythema migrans (early Lyme borreliosis) were enrolled in a randomised prospective trial comparing amoxycillin 500 mg plus probenecid 500 mg three times a day with doxycycline 100 mg twice a day for 21 days. These antibiotic regimens were chosen because of the known in-vitro sensitivity of Borrelia burgdorferi, the antibiotic tissue penetration, the pharmacokinetics of the drugs, and because the organism can disseminate early in the course of infection. 72 patients were evaluable (35 in the doxycycline group and 37 in the amoxycillin/probenecid group). The two regimens were equally effective for treatment of erythema migrans. Mild fatigue or arthralgia were the only post-treatment complaints, which resolved within 6 months. None of the patients needed further antibiotic treatment for Lyme borreliosis.