When occurring between two parts of the intestine, it is known as an enteroenteral fistula, between the small intestine and the skin as an enterocutaneous fistula, and between the small intestine and the colon as a colocutaneous fistula.The following list is sorted by the International Statistical Classification of Diseases and Related Health Problems. H: Diseases of the eye, adnexa, ear, and mastoid process
(H04.6) Lacrimal fistula
(H05.81) Carotid cavernous fistula
(H70.1) Mastoid fistula
Craniosinus fistula: between the intracranial space and a paranasal sinus
(H83.1) Labyrinthine fistula
Perilymph fistula: tear between the membranes between the middle and inner ears
Preauricular fistula
Preauricular fistula: usually on the top of the cristae helicis of the ears

I: Diseases of the circulatory system
(I25.4) Coronary arteriovenous fistula, acquired
(I28.0) Arteriovenous fistula of pulmonary vessels
Pulmonary arteriovenous fistula: between an artery and vein of the lungs, resulting in shunting of blood. This results in improperly oxygenated blood. (I67.1) Cerebral arteriovenous fistula, acquired
(I77.0) Arteriovenous fistula, acquired
(I77.2) Fistula of artery

J: Diseases of the respiratory system
(J86.0) Pyothorax with fistula
(J95.0) Tracheoesophageal fistula, between the trachea and the esophagus. This may be congenital or acquired, for example as a complication of a tracheostomy. K: Diseases of the digestive system
(K11.4) Salivary gland fistula
(K31.6) Fistula of stomach and duodenum
(K31.6) Gastrocolic fistula
(K31.6) Gastrojejunocolic fistula – after a Billroth II a fistula forms between the transverse colon and the upper jejunum (which, post Billroth II, is attached to the remainder of the stomach). Fecal matter passes improperly from the colon to the stomach and causes halitosis.
(1) The sandflies inject the infective stage, metacyclic promastigotes, during blood meals. (2) Metacyclic promastigotes in the puncture wound are phagocytized by macrophages, and (3) transform into amastigotes. (4) Amastigotes multiply in infected cells and affect different tissues, depending in part on the host, and in part on which Leishmania species is involved. These differing tissue specificities cause the differing clinical manifestations of the various forms of leishmaniasis. (5,6) Sandflies become infected during blood meals on infected hosts when they ingest macrophages infected with amastigotes. (7) In the sandflys midgut, the parasites differentiate into promastigotes, (8) which multiply, differentiate into metacyclic promastigotes, and migrate to the proboscis. The genomes of three Leishmania species (L. major, L. infantum, and L. braziliensis) have been sequenced, and this has provided much information about the biology of the parasite. For example, in Leishmania, protein-coding genes are understood to be organized as large polycistronic units in a head-to-head or tail-to-tail manner; RNA polymerase II transcribes long polycistronic messages in the absence of defined RNA pol II promoters, and Leishmania has unique features with respect to the regulation of gene expression in response to changes in the environment. The new knowledge from these studies may help identify new targets for urgently needed drugs and aid the development of vaccines. Vector
Although most of the literature mentions only one genus transmitting Leishmania to humans (Lutzomyia) in the New World, a 2003 study by Galati suggested a new classification for New World sand flies, elevating several subgenera to the genus level.