Most of Kansas has been declared a high risk for West Nile Virus (WNV) and the disease has been reported in domestic animals including cats. I think this is a risk worth mentioning. I don’t know how commonly domestic cats are infected but there is a risk. It is also present in other areas of the USA.
The disease is transmitted by a mosquito bite or by a cat eating infected small mammals such as mice and probably birds.
abcdcatsvets.org report that most infected animals do not show observable symptoms, ‘most infections are subclinical in nature’.
It seems that sometimes mild, non-specific signs of illness are present including lethargy and a decrease in appetite during the first week after becoming infected.
Dogs are also at risk. There appears to be no diagnostic test for WNV but in acute infections virus-specific IgM antibodies can be detected most likely during the later stages of the infection.
My reading of WNV in cats is that it will be difficult to diagnose and the cat will present with unspecific signs of illness. It is therefore something to bear in mind as an option if the cat lives in Kansas and he is feeling unwell.
WNV comes from the West Nile district of Uganda. It was spread to America by migratory birds. The disease is maintained in a bird-mosquito-bird transmission cycle.