Stephen L. Doggett

SUMMARY: Since the late 1990s, bed bugs of the speciesCimex lectulariusandCimex hemipterushave undergone a worldwide resurgence. These bed bugs are blood-sucking insects that readily bite humans. Cutaneous reactions may occur and can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, which are accompanied by intense itching. Occasionally, bullous eruptions may result. If bed bugs are numerous, the patient can present with widespread urticaria or eythematous rashes. Often, bites occur in lines along the limbs. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. Anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health, while the insect itself can be the cause of significant psychological trauma. The control of bed bugs is challenging and should encompass a multidisciplinary approach utilizing nonchemical means of control and the judicious use of insecticides. For accommodation providers, risk management procedures should be implemented to reduce the potential of bed bug infestations.

Australia has experienced a sudden and unexpected resurgence in bed bug infestations from both Cimex lectularius L. and Cimex hemipterus F. A survey in 2006 revealed that infestations had increased across the nation by an average of 4,500% since the start of the decade. In response, a multi-disciplinary approach to combat the rise of this public health pest was implemented and involved the coordinated efforts of several organizations. The key components of the strategy included the introduction of a pest management standard ‘A Code of Practice for the Control of Bed Bug Infestations in Australia’ that defines and promotes ‘best practice’ in bed bug eradication, the development of a policy and procedural guide for accommodation providers, education of stakeholders in best management practices, and research. These strategies continue to evolve with developments that lead to improvements in ‘best practice’ while bed bugs remain problematic in Australia.

Since the mid 1990s, there has been a global resurgence of bed bugs (Cimex spp.), which are blood feeding insects that readily bite humans. Patients suffering with bite reactions are increasingly presenting to medical practitioners. This article reviews the various clinical consequences of bed bug bites and outlines management strategies. Common dermatological responses include the early development of small macular spots that may later progress into prominent wheals accompanied by intense itching. Patients exposed to numerous bed bugs can present with a widespread erythematous rash or urticaria. Bullous eruptions are not uncommon and anaphylaxis has been reported, albeit rarely. There is no evidence that bed bugs transmit human pathogens, but they are responsible for significant psychological distress, can produce anaemia when abundant, and have been implicated in the triggering of asthmatic reactions. Symptomatic control involves treatment of the patient with antihistamines and corticosteroids, and ensuring that the infestation responsible for the problem is effectively eliminated.

The vector competence of Verrallina carmenti (Edwards), Verrallina lineata (Taylor), and Mansonia septempunctata (Theobald) (Diptera: Culicidae) from north Queensland, Australia, was tested using two isolates of Ross River virus (family Togaviridae, genus Alphavirus, RRV). All three species were tested using RRV isolate RR102MP (ex-Cairns, Queensland, Australia), whereas Ve. carmenti and Ve. lineata also were tested using RR2186 (ex-Bourke, New South Wales, Australia). Transmission was tested using the capillary tube method, with infection of mosquito bodies and saliva determined using cell culture. Infection with RR102MP resulted in 27.5% of Ve. carmenti, 19.2% of Ve. lineata and 13.3% of Ma. septempunctata transmitting virus. When Ve. carmenti and Ve. lineata were infected with RR2186, transmission rates for both species were generally < 10%, although a transmission rate of 25% was recorded for Ve. lineata exposed to high titer virus. These results indicated that the three mosquito species have the potential to contribute to local transmission cycles.