title: Parasitological, Hematological and Biochemical Characteristics of a Model of Hyper-microfilariaemic Loiasis (Loa loa) in the Baboon (Papio anubis).
abstract: BACKGROUND
  Loiasis, a filarial infection caused by Loa loa usually thought to cause relatively minor morbidity, can cause serious and often fatal reactions in patients carrying very high levels of circulating Loa loa microfilariae (mf) following administration of microfilaricidal drugs. An experimental model of this condition would greatly aid the definition of the optimal management of this important clinical presentation.
  
  
  RESULTS
  Fifteen baboons (Papio anubis) were infected with 600 infective larvae (L3) isolated from Chrysops vector flies. Animals were observed for any clinical changes; blood samples were collected every 1-2 months for 22 months, and analysed for parasitological, hematological and biochemical profiles using standard techniques. All animals became patent but remained clinically normal throughout the study. The parasitological pre-patent period was between 4-8 months, with a majority (60%) of animals becoming patent by 5 months post infection (MPI); all animals were patent by 8 MPI. Microfilarial loads increased steadily in all animals and reached a peak at 18 MPI. By 10 MPI >70% of animals had mf >8,000 mf/mL, and at 18 MPI >70% of animals had mf >30,000 mf/mL with 50% of these animals with mf >50,000 mf/mL. Absolute eosinophil, creatinine, Ca2+ and K+ levels were generally above normal values (NV). Positive associations were seen between microfilariaemia and eosinophilia, Hb, Ca2+, and gamma-GT values, whilst significant negative associations were seen between microfilariaemia and potassium, glucose and mononuclear leukocyte levels.
  
  
  CONCLUSIONS
  Infection of splenectomised baboons with L. loa can induce levels of circulating microfilariae, and corresponding haematological profiles, which parallel those seen in those humans in danger of the severe post-microfilariacide clinical responses. Utilization of this experimental model could contribute to the improved management of the loiasis related adverse responses in humans.
authors.affiliation: Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, South West Region, Cameroon.|Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Samuel
authors.initials: S
authors.lastname: Wanji
authors.affiliation: Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.|Department of Biological Sciences, Faculty of Science, University of Bamenda, North West Region, Cameroon.|Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, South West Region, Cameroon.
authors.forename: Ebanga-Echi
authors.initials: EE
authors.lastname: Eyong
authors.affiliation: Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, South West Region, Cameroon.|Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Tendongfor
authors.affiliation: Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Che
authors.initials: C
authors.lastname: Ngwa
authors.affiliation: Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Elive
authors.initials: E
authors.lastname: Esuka
authors.affiliation: Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, South West Region, Cameroon.|Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Kengne-Ouafo
authors.affiliation: Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, South West Region, Cameroon.|Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Datchoua-Poutcheu
authors.affiliation: Parasites and Vectors Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, South West Region, Cameroon.|Research Foundation for Tropical Diseases and Environment (REFOTDE), South West Region, Cameroon.
authors.forename: Peter
authors.initials: P
authors.lastname: Enyong
authors.affiliation: Mectizan Donation Programme, Decatur, Georgia, United States of America.
authors.forename: Adrian
authors.initials: A
authors.lastname: Hopkins
authors.affiliation: Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Mackenzie
mesh_terms: D000818:Animals; D001769:Blood / Q000469:parasitology; D001774:Blood Chemical Analysis; D004175:Diptera / Q000469:parasitology; D004195:Disease Models, Animal; D004802:Eosinophilia; D005260:Female; D008118:Loiasis / Q000469:parasitology* / Q000473:pathology*; D008297:Male; D008842:Microfilariae / Q000302:isolation & purification; D048530:Papio anubis; D059208:Parasite Load