These studies may help to better understand the immune response to F. hepatica in host and are necessary in development of vaccine against the parasite. It has been established that cattle acquire resistance to challenge infection with F. hepatica and F. gigantica when they have been sensitized with primary patent or drug-abbreviated infection. Resistance to fasciolosis was also documented in rats. On the other hand, sheep and goats are not resistant to re-infection with F. hepatica. However, there is evidence that two sheep breeds, in particular Indonesian thin tail sheep and Red maasai sheep, are resistant to F. gigantica. Diagnosis
Most immunodiagnostic tests will detect infection and have a sensitivity above 90% during all stages of the diseases. In addition antibody concentration quickly drops post treatment and no antibodies are present one year after treatment, which makes it a very good diagnostic method. In humans, diagnosis of fasciolosis is usually achieved parasitologically by findings the fluke eggs in stool, and immunologically by ELISA and Western blot. Coprological examinations of stool alone are generally not adequate because infected humans have important clinical presentations long before eggs are found in the stools.Moreover, in many human infections, the fluke eggs are often not found in the faeces, even after multiple faecal examinations. Furthermore, eggs of F. hepatica, F. gigantica and Fasciolopsis buski are morphologically indistinguishable. Therefore, immunonological methods such ELISA and enzyme-linked immunoelectrotransfer blot, also called Western blot, are the most important methods in diagnosis of F. hepatica infection.
Uncommon, except in lower socioeconomic classes, this typically affects adolescents and young adults, especially in institutions, armed forces, etc., or people with HIV/AIDS. The disease has occurred in epidemic-like patterns, but it is not contagious. History
Necrotizing ulcerative gingivitis has been observed for centuries. Xenophon observes sore mouth and foul smelling breath in Greek soldiers in the 4th century BC. Hunter describes the clinical features of ANUG in 1778, differentiating it from scurvy (avitaminosis C) and chronic periodontitis. Jean Hyacinthe Vincent, a French physician working at the Paris Pasteur Institute describes a fusospirochetal infection of the pharynx and palatine tonsils, causing "ulcero-membranous pharyngitis and tonsillitis", which later became known as Vincents angina. Later in 1904, Vincent describes the same pathogenic organisms in "ulceronecrotic gingivitis". Vincents angina is sometimes confused with NUG, however the former is tonsillitis and pharyngitis, and the latter involves the gums, and usually the two conditions occur in isolation from each other. The term trench mouth evolved because the disease was observed in front line soldiers during World War I, thought to be a result at least partly because of extreme psychologic stress they were exposed to. The same condition was appearing in civilians during periods of bombing raids, who were away from the front line, and who had relatively good diets during wartime due to rationing, so it is assumed that psychologic stress was the significant causative factor. It has also been associated with high tobacco use in the army.