Ticks and Tick-borne Diseases 3 (2012) 207–211 Contents lists available at SciVerse ScienceDirect Ticks and Tick-borne Diseases journa l h o mepage: www.elsevier.de/ttbdis Original article Haematological parameters in stray dogs seropositive and seronegative to Ehrlichia canis in North Trinidad Zinora Asgarali a,∗ , Indira Pargass a , Judy Adam b , Alexander Mutani a , Chukwudozie Ezeokoli b a Department of Basic Clinical Sciences, School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, Trinidad and Tobago b Department of Clinical Medicine, School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, Trinidad and Tobago a r t i c l e i n f o Article history: Received 8 December 2010 Received in revised form 12 March 2012 Accepted 13 March 2012 Keywords: Ehrlichia canis Haematology Stray dogs Indirect immunofluorescent antibody test a b s t r a c t In view of the fact that stray dogs are a reservoir for many diseases, this study was undertaken to deter- mine the prevalence of Ehrlichia canis in stray dogs in North Trinidad and to evaluate the diagnostic implications of haematological alterations associated with seropositivity. Overall, 41 (44.6%) of 92 stray dogs were seropositive to E. canis by the indirect immunofluorescent antibody test. Dogs, one year of age and older (59.7%) were more likely to be seropositive than dogs less than one year old (13.3%) (p < 0.001). No significant differences in seropositivity between females and males were found. The odds ratios showed that seropositive dogs were 3.34 (CI 95%; 1.33–8.59) and 5.17 (CI 95%; 0.19–1.26) times more likely to have low platelet counts and elevated total serum protein concentrations (p = 0.014 and p < 0.001, respectively) than seronegative dogs. Lower mean platelet counts and a higher mean total protein concen- tration were associated with seropositivity (p < 0.01). Mean eosinophil and segmented neutrophil counts were elevated in dogs that tested negative for E. canis antibodies (p = 0.002 and p < 0.005, respectively). Other haematological parameters were not different between the 2 groups. The high percentage of stray dogs infected with E. canis should alert veterinarians to the potential risk of transmission of the disease. A comprehensive study possibly using molecular methods such as nested PCR should be undertaken to determine how co-infection with other pathogens may alter haematological profiles. In general, control of ticks and stray dog populations may help to control the spread of tick-borne diseases. © 2012 Elsevier GmbH. All rights reserved. Introduction Tick-borne diseases continue to pose a serious health haz- ard for companion animals and humans worldwide (Jongejan and Uilenberg, 2004). In Trinidad, a small island located to the north of Venezuela and at the southern tip of the chain of Caribbean islands, dogs are used for security purposes, as companion ani- mals, and for shows and hunting. Usually, dogs in the Caribbean are kept outdoors and left to roam, thus adding to the abundance of the stray population and increasing their exposure to ticks, uncon- trolled breeding and neutering (Fielding and Ostberg, 2012). While large numbers of stray dogs are frequently seen in urban and rural areas of Trinidad, their prevalence at present is not known. These dogs in general tend to harbour large tick loads, most commonly the brown dog tick, Rhipicephalus sanguineus, a vector for a number of pathogens found worldwide (Baneth et al., 1996; Waner et al., 1999). This tick transmits the obligate intracellular rickettsia E. ∗ Corresponding author at: School of Veterinary Medicine, Faculty of Medical Sci- ences, University of the West Indies, Trinidad, Trinidad and Tobago. Tel.: +868 645 2640x4236; fax: +868 645 7428. E-mail addresses: zinora.asgarali@sta.uwi.edu, zinoraa@yahoo.com (Z. Asgarali). canis, which causes severe clinical complications of canine mono- cytic ehrlichiosis (CME) (Groves et al., 1975). Although E. canis is more prevalent in tropical and subtropical areas in India, Asia, South America, and Africa (Sidoti and Tringali, 2009), it has recently been more frequently detected in Europe and Canada, possibly due to altered geographic distribution of ticks, importation of animals, and changing climatic conditions (Parola et al., 2008; Gary et al., 2006). In recent times, infections with E. canis have become a public health concern, since contact with humans have resulted in the identifi- cation of an organism genetically and morphologically similar to E. canis in an infected person in Venezuela (Unver et al., 2001). Within the Caribbean, the prevalence of E. canis varies among the islands. In Grenada and Trinidad, E. canis was detected by PCR in 25% and 14.1% of dogs, respectively (Yabsley et al., 2008; Georges et al., 2008). In Trinidad, infestation with R. sanguineus is not seasonal, but is a major problem throughout the year. Many dogs seen at vet- erinary clinics are treated for E. canis infection based solely on clinical signs and typical haematological abnormalities such as anaemia, neutropenia, and thrombocytopenia (Harrus and Waner, 2011). Since natural infection in dogs may present with a vari- ety of clinical signs which vary between various geographical regions, it is difficult to make a definitive diagnosis based on clini- cal and haematological abnormalities alone. Based on experimental 1877-959X/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.ttbdis.2012.03.006