The genetic material of WNV is a positive-sense, single strand of RNA, which is between 11,000 and 12,000 nucleotides long; these genes encode seven nonstructural proteins and three structural proteins. The RNA strand is held within a nucleocapsid formed from 12-kDa protein blocks; the capsid is contained within a host-derived membrane altered by two viral membrane proteins.West Nile virus has been seen to replicate faster and spread more easily to birds at higher temperatures; one of several ways climate change could affect the epidemiology of this disease. Transmission
The prime method of spread of the West Nile virus (WNV) is the female mosquito. In Europe, cats were identified as being hosts for West Nile virus. The important mosquito vectors vary according to area; in the United States, Culex pipiens (Eastern United States, and urban and residential areas of the United States north of 36–39°N), Culex tarsalis (Midwest and West), and Culex quinquefasciatus (Southeast) are the main vector species.The mosquito species that are most frequently infected with WNV feed primarily on birds. Different species of mosquitos take a blood meal from different types of vertebrate hosts, Mosquitoes show further selectivity, exhibiting preference for different species of birds. In the United States, WNV mosquito vectors feed preferentially on members of the Corvidae and thrush family.
Gingivitis associated with plaque only
Gingival diseases modified by systemic factors
Gingival diseases modified by medications
Gingival diseases modified by malnutrition
Non-plaque-induced gingival lesions
Gingival diseases of specific bacterial origin
Gingival diseases of viral origin
Gingival diseases of fungal origin
Gingival diseases of genetic origin
Gingival manifestations of systemic conditions
Traumatic lesions
Foreign body reactions
Not otherwise specified

2017 Classification
As defined by the 2017 World Workshop, periodontal health, gingival diseases/ conditions have been categorised into the following:
Periodontal health and gingival health
Clinical gingival health on an intact periodontium
Clinical gingival health on a reduced periodontium
Stable periodontitis patient
Non-periodontitis patient
Gingivitis – dental biofilm-induced
Associated with dental biofilm alone
Mediated by systemic or local risk factors
Drug-influenced gingival enlargement
Gingival diseases – non-dental biofilm induced
Genetic/ developmental disorders
Specific infections
Inflammatory and immune conditions
Reactive processes
Neoplasms
Endocrine, nutritional & metabolic diseases
Traumatic lesions
Gingival pigmentation

Prevention
Gingivitis can be prevented through regular oral hygiene that includes daily brushing and flossing. Hydrogen peroxide, saline, alcohol or chlorhexidine mouth washes may also be employed. In a 2004 clinical study, the beneficial effect of hydrogen peroxide on gingivitis has been highlighted. The use of oscillation type brushes might reduce the risk of gingivitis compared to manual brushing.Rigorous plaque control programs along with periodontal scaling and curettage also have proved to be helpful, although according to the American Dental Association, periodontal scaling and root planing are considered as a treatment for periodontal disease, not as a preventive treatment for periodontal disease. In a 1997 review of effectiveness data, the U.S. Food and Drug Administration (FDA) found clear evidence showing that toothpaste containing triclosan was effective in preventing gingivitis.