BACKGROUND: Hepatozoonosis of domestic cats has been reported in several countries, mainly as a subclinical infection.
UNASSIGNED: Infection has been described mostly in areas where canine infection is present and, in recent years, Hepatozoon felis has been identified as a distinct species by molecular techniques. The vector for feline hepatozoonosis remains unknown and the pathogenesis has not been elucidated.
UNASSIGNED: Feline hepatozoonosis is mainly a subclinical infection and few cases have been reported with clinical signs. The diagnosis of hepatozoonosis in cats can be made by observation of parasite gamonts in blood smears, parasite meronts in muscles by histopathology, and detection of parasite DNA in blood and tissue by PCR.
METHODS: The treatment of choice is not known, but single cases have been treated with doxycycline or oxytetracycline and primaquine. Although the mode of transmission and the type of vector is not known, preventive treatment against blood-sucking vectors (fleas and ticks) is advised.

These second edition guidelines, updated from the 2007 version (Marchiondo et al., 2007), are intended to assist the planning and conduct of laboratory and clinical studies to assess the efficacy of ectoparasiticides applied to dogs or cats for the purpose of treating, preventing and controlling flea and tick infestations. Major revisions to this second edition include guidelines on the assessment of systemic flea and tick products, an update of the geographical distribution of the common fleas and ticks species on dogs and cats, determination of flea and tick efficacy based on geometric versus arithmetic means with respect to geographic regulatory agencies, modification of tick categorization in the assessment of efficacy, expanded guidelines on repellency and anti-feeding effects, enhanced practical field study guidance, and considerations on the ranges of flea and ticks for infestations in laboratory studies. The term ectoparasiticide includes insecticidal and acaricidal compounds, as well as insect growth regulators. The range of biological activities from animal treatment that are considered include: repellency and anti-feeding effects, knockdown, speed of kill, immediate and persistent lethal effects, and interference with egg fertility and subsequent development of off-host life cycle stages. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping, interpretation of results and animal welfare. These guidelines are also intended to assist regulatory authorities involved in the approval and registration of new topical or systemic ectoparasiticides, and to facilitate the worldwide adoption of harmonized procedures.