All biological phenomenon has both proximate cause and ultimate cause. Traditional veterinary medicine focuses proximate cause of disease. Evolutionary medicine deals ultimate cause of disease. This article introduces concepts and two themes of evolutionary medicine, infectious disease and host defense, mismatch with environment of evolutionary adaptedness（EEA). In clinical medicine of captive wild lives, mismatch with EEA is important to understand etiology of species specific diseases which captive ones are susceptible. Gastritis syndrome is a popular disease in captive cetaceans. Many factors have been suggested but specific etiology has been unknown. Captive cetaceans feed in day which humans are active, however free ranging counterparts forage day-and-night. I hypothesize that unusual situations differs from wilds may cause prolonged low pH in forestomach of captive cetaceans and make gastritis in them. My own experiences seem support some parts of the hypothesis. Evolutionary medicine may give rewarding insights into wildlife medicine, but critical attitudes and alternative hypothesis should be kept in mind to prevent its easy application.
Nineteen wild male Siberian weasels (Mustela sibirica coreana), collected from August 1997 to April 2011 in Tsushima Islands, were used for this study. The testes and baculum were measured, and testicular samples were autopsied and observed histologically. In the subadult, testes size and seminiferous tubule diameter tended to increase rapidly from November, peaking around February. In the adult, testes size and seminiferous tubule diameter tended to be large from February to June, and small from September to around January. Because young animals contain spermatozoa in the epididymis after April, they appear to attain sexual maturity around April of the year after birth. The baculum of the adult of this species has developed a hook-shaped distal tip and spatulate base.
Encysted nematode larvae were found from muscle of two Peregrine Falcons rescued in Kumamoto Prefecture, Japan. They were identified morphologically as the advanced third-stage larvae of Gnathostoma spinigerum and G. nipponicum. This is the first case of Gnathostoma infection in Peregrine Falcons. The falcons were considered to acquire the infection by ingestion of other infected birds.
Two free-ranging Ryukyu long-furred rats that were suspected to be killed from traffic accidents in Kunigami-son, Okinawa Prefecture, Japan were collected in September 2011. At necropsy, many macroscopic sarcocysts were observed in the skeletal muscles of these two animals, such as the tongue, masseter muscle, diaphragm, and external oblique muscle. Histological examination found no inflammatory reactions around the sarcocyst. By DNA sequencing of these sarcocysts, two 1,797 base pairs (bp) of the 18S rRNA gene (GenBank accession number AB691780) and two 1,441-bp fragments of the 28S rRNA gene (GenBank accession number AB691781) of Sarcocystis sp. were obtained. The 18S and 28S rRNA gene sequences of the parasite collected from different host individuals were absolutely identical. This is the first record of sarcocystosis in the Ryukyu long-furred rat, which is a rare and endemic species of the Nansei Islands, Japan.