Treatment of dogs infected with Hepatozoon americanum: 53 cases (1989-1998).
OBJECTIVE
To determine clinical and pathologic findings before and after short-term (group 1) and long-term (group 2) treatment in dogs with Hepatozoon americanum infection.


METHODS
Retrospective study.


METHODS
53 dogs with H. americanum infection.


METHODS
Medical records of dogs that were treated for hepatozoonosis diagnosed on the basis of meront or merozoite stages in skeletal muscle were reviewed.


RESULTS
Circulating gametocytes of H. americanum were identified in 12 of 53 dogs. Dogs were treated with various drugs, including toltrazuril, trimethoprim-sulfadiazine, clindamycin, pyrimethamine, and decoquinate. Mean WBC counts prior to treatment were 85,700 and 75,200 cells/microl in groups 1 and 2, respectively, and 1 month after initiation of treatment were 12,600 and 14,600 cells/microl, respectively. Initial response to treatment was excellent in all dogs. Twenty-three of 26 dogs in group 1 relapsed at least once and died within 2 years; mean (+/- SD) survival time was 12.6+/-2.2 months. Twenty-two of 27 group-2 dogs survived; 11 dogs had no clinical signs and were still receiving decoquinate (mean duration of treatment, 21 months), 11 dogs had no clinical signs after treatment for 14 months (range, 3 to 33 months; mean survival time, 39 months [range, 26 to 53 months]), 2 dogs were lost to follow-up, and 3 dogs were euthanatized because of severe disease.


CONCLUSIONS
Although no treatment effectively eliminated the tissue stages of H. americanum, treatment with trimethoprim-sulfadiazine, clindamycin, and pyrimethamine followed by long-term administration of decoquinate resulted in extended survival times and excellent quality of life.
Macintire
D K
DK
Department of Small Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, AL 36849, USA.
Vincent-Johnson
N A
NA
Kane
C W
CW
Lindsay
D S
DS
Blagburn
B L
BL
Dillon
A R
AR
D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000892:Anti-Infective Agents, Urinary / Q000008:administration & dosage / Q000627:therapeutic use; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001786:Blood Glucose / Q000032:analysis; D001831:Body Temperature; D001835:Body Weight; D002981:Clindamycin / Q000008:administration & dosage / Q000627:therapeutic use; D003044:Coccidia / Q000187:drug effects*; D003048:Coccidiosis / Q000188:drug therapy / Q000662:veterinary*; D003049:Coccidiostats / Q000008:administration & dosage / Q000627:therapeutic use*; D003667:Decoquinate / Q000008:administration & dosage / Q000627:therapeutic use; D004283:Dog Diseases / Q000188:drug therapy* / Q000469:parasitology; D004285:Dogs; D005260:Female; D006400:Hematocrit / Q000662:veterinary; D007958:Leukocyte Count / Q000662:veterinary; D008297:Male; D011739:Pyrimethamine / Q000008:administration & dosage / Q000627:therapeutic use; D012008:Recurrence; D012189:Retrospective Studies; D012709:Serum Albumin / Q000032:analysis; D013411:Sulfadiazine / Q000008:administration & dosage / Q000627:therapeutic use; D016019:Survival Analysis; D014295:Trimethoprim / Q000008:administration & dosage / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D000892:Anti-Infective Agents, Urinary; D000981:Antiprotozoal Agents; D001786:Blood Glucose; D003049:Coccidiostats; D012709:Serum Albumin; D013411:Sulfadiazine; D002981:Clindamycin; D003667:Decoquinate; D014295:Trimethoprim; D000469:Alkaline Phosphatase; D011739:Pyrimethamine