Localised Mycobacterium ulcerans infection in a cat in Australia.

A 10-year-old castrated male domestic cat domiciled in eastern Victoria (Australia) was presented for a subcutaneous mass on its nasal bridge in November 2006. Cytological examination of an aspirate demonstrated pyogranulomatous inflammation. At surgery, the lesion consisted of an encapsulated mass containing viscid fluid. Histological examination of the resected lesion revealed pyogranulomatous inflammation surrounding a central zone of necrosis. Sections stained with the Ziehl-Neelsen method revealed numerous acid-fast bacilli, intracellularly within macrophages and extracellularly. Molecular studies established the infection was caused by Mycobacterium ulcerans. As histology demonstrated that the infection extended to the margin of the excised tissues, the cat was treated subsequently with clarithromycin (62.5mg orally once daily for 7 days, then twice daily for 3 months). The surgical wound healed unremarkably. The infection has not recurred at the time of writing, 1 year following discontinuation of treatment. Although M ulcerans infections have been recorded in variety of mammals, this is the first known case in a cat.

Climate and landscape factors associated with Buruli ulcer incidence in Victoria, Australia.

BACKGROUND: Buruli ulcer (BU), caused by Mycobacterium ulcerans (M. ulcerans), is a necrotizing skin disease found in more than 30 countries worldwide. BU incidence is highest in West Africa; however, cases have substantially increased in coastal regions of southern Australia over the past 30 years. Although the mode of transmission remains uncertain, the spatial pattern of BU emergence in recent years seems to suggest that there is an environmental niche for M. ulcerans and BU prevalence. METHODOLOGY/PRINCIPAL FINDINGS: Network analysis was applied to BU cases in Victoria, Australia, from 1981-2008. Results revealed a non-random spatio-temporal pattern at the regional scale as well as a stable and efficient BU disease network, indicating that deterministic factors influence the occurrence of this disease. Monthly BU incidence reported by locality was analyzed with landscape and climate data using a multilevel Poisson regression approach. The results suggest the highest BU risk areas occur at low elevations with forested land cover, similar to previous studies of BU risk in West Africa. Additionally, climate conditions as far as 1.5 years in advance appear to impact disease incidence. Warmer and wetter conditions 18-19 months prior to case emergence, followed by a dry period approximately 5 months prior to case emergence seem to favor the occurrence of BU. CONCLUSIONS/SIGNIFICANCE: The BU network structure in Victoria, Australia, suggests external environmental factors favor M. ulcerans transmission and, therefore, BU incidence. A unique combination of environmental conditions, including land cover type, temperature and a wet-dry sequence, may produce habitat characteristics that support M. ulcerans transmission and BU prevalence. These findings imply that future BU research efforts on transmission mechanisms should focus on potential vectors/reservoirs found in those environmental niches. Further, this study is the first to quantitatively estimate environmental lag times associated with BU outbreaks, providing insights for future transmission investigations.

Charles Darwin's impressions of New Zealand and Australia, and insights into his illness and his developing ideas on evolution.

Charles Darwin visited New Zealand in December 1835, and Australia from January until March 1836, on the return portion of his voyage around the world in HMS Beagle. Despite the shortness of these visits, he retained an interest in these countries throughout his life, maintaining correspondence and receiving many biological specimens. His experiences in these places influenced his thinking on evolution, particularly on the evolution of man. Aspects of his health recorded during this part of the voyage support a new hypothesis for the diagnosis of the illness that Darwin endured for most of his life.

First case of Mycobacterium ulcerans disease (Bairnsdale or Buruli ulcer) acquired in New South Wales.

Mycobacterium ulcerans is a slow-growing environmental bacterium that causes Buruli ulcer (also known as Bairnsdale ulcer in Victoria and Daintree ulcer in northern Queensland). We describe two patients with laboratory-confirmed Buruli ulcer who were infected either in New South Wales or overseas. A molecular epidemiological investigation demonstrated that, while one case was probably acquired in Papua New Guinea, the other was most likely to have been acquired in southern NSW. To our knowledge, this is the first case of M. ulcerans infection acquired in NSW.

Consensus recommendations for the diagnosis, treatment and control of Mycobacterium ulcerans infection (Bairnsdale or Buruli ulcer) in Victoria, Australia.

Mycobacterium ulcerans causes slowly progressive, destructive skin and soft tissue infections, known as Bairnsdale or Buruli ulcer (BU). Forty-six delegates with experience in the management of BU attended a 1-day conference in Melbourne on 10 February 2006, with the aim of developing a consensus approach to the diagnosis, treatment and control of BU. An initial draft document was extended and improved during a facilitated round table discussion. BU is an environmental infection that occurs in specific locations. The main risk factor for infection is contact with an endemic area. Prompt cleaning of abrasions sustained outdoors, wearing protective clothing, and avoiding mosquito bites may reduce an individual's risk of infection. BU can be rapidly and accurately diagnosed by polymerase chain reaction testing of ulcer swabs or biopsies. Best outcomes are obtained when the diagnosis is made early. To aid early diagnosis, health authorities should keep local populations informed of new outbreaks. BU is best treated with surgical excision, which, if possible, should include a small rim of healthy tissue. For small lesions this may be all that is required. However, there is a role for antibiotics for more extensive disease, and their use may allow more conservative surgery.

Mycobacterium ulcerans in mosquitoes captured during outbreak of Buruli ulcer, southeastern Australia.

Buruli ulcer (BU) occurs in >30 countries. The causative organism, Mycobacterium ulcerans, is acquired from the environment, but the exact mode of transmission is unknown. We investigated an outbreak of BU in a small coastal town in southeastern Australia and screened by PCR mosquitoes caught there. All cases of BU were confirmed by culture or PCR. Mosquitoes were trapped in multiple locations during a 26-month period. BU developed in 48 residents of Point Lonsdale/Queenscliff and 31 visitors from January 2001 through April 2007. We tested 11,504 mosquitoes trapped at Point Lonsdale (predominantly Aedes camptorhynchus). Forty-eight pools (5 species) were positive for insertion sequence IS2404 (maximum likelihood estimate 4.3/1,000), and we confirmed the presence of M. ulcerans in a subset of pools by detection of 3 additional PCR targets.