title: Avian and simian malaria: do they have a cancer connection?
abstract: It has been claimed that infectious agents transmitted by mosquitoes (Diptera: Culicidae) may have a greater connection to cancer then hitherto supposed and that the immune system struggles to recognize and fight some of these infectious agents. One of the claims made is that there is a connection between human malaria and brain cancers in the USA. However, the USA declared itself free of human malaria in the last century, yet cancer incidences remain high, suggesting any overall cancer connection is slight. Two fundamental questions arise from the possible mosquito-cancer connection. Firstly, if mosquitoes are able to vector some pathogens and parasites linked with cancer pathogenesis, why has the fact not been discovered decades ago? Secondly, if there is a connection (other than in relation to Burkett's lymphoma), what is its extent? The answers may well lie with the various types of malarias known to exist. The discovery in humans of the simian malaria, caused by Plasmodium knowlesi, suggests that other forms of simian or even avian malaria may be capable of survival in humans, albeit at low levels of parasitemia, and humans may be a dead-end host. Other carcinogenic infectious agents transmitted by mosquitoes may also go undetected because either no one is looking for them, or they are looking in wrong anatomical locations and/or with inadequate tools. Research on false negative test results with respect to many infectious agents is sadly lacking, so its extent is unknown. However, electronic and other media provide numerous instances of patients failing to be diagnosed for both human malaria and Lyme's disease, to take just two examples. This review suggests that to shed light on a potential mosquito-cancer connection, more research is required to establish whether other simian and avian forms of malaria play a part. If so, then they potentially provide unique markers for early cancer detection.
authors.affiliation: The Pain Clinic, Bolsover, S44 6BB, UK. martin@martinward200.plus.com.
authors.forename: Martin
authors.initials: M
authors.lastname: Ward
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124, Pisa, Italy. benelli.giovanni@gmail.com.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Benelli
mesh_terms: D000818:Animals; D001717:Birds; D009033:Culicidae / Q000469:parasitology; D006801:Humans; D008288:Malaria / Q000469:parasitology* / Q000635:transmission; D008289:Malaria, Avian / Q000469:parasitology* / Q000635:transmission; D009369:Neoplasms / Q000469:parasitology*; D016790:Plasmodium knowlesi / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*
keywords: Avian malaria; Carcinogenic infectious agents; Mosquitoes; Parasites; Simian malaria