[Show abstract][Hide abstract] ABSTRACT: Ixodid tick transmitted ehrlichiosis has a broad host range that includes humans, domestic animals and wild animals such as Deer (Belongia et al. 1997), Lions (Buoro et al. 1994), Lemurs (Williams et al. 2002), Rhesus Macaques (Lewis et al. 1975) and Baboons (Lewis et al. 1975). Although the disease has been recorded in nonhuman primates from other parts of the globe, information is lacking from Indian subcontinent. Langurs are distributed from the Himalaya to Cape Comorin with the exception of the western deserts (Prater 1990), and they may act as a blood reservoir by infecting ticks for subsequent transmission to other mammals. The present communication reports the occurrence of Ehrlichia infection in a langur (Semnopithecus sp.) from Nagpur District of Maharashtra State. A severely injured and anaemic langur from Nagpur was presented for treatment at Nagpur Veterinary College Hospital, Nagpur. Clinical and radiological examination revealed fracture in a forelimb, which was removed surgically. The animal did not survive and succumbed to its injuries. A post-mortem examination was performed within an hour after death and blood smears were prepared from heart blood, stained with Leishmans stain and examined under a microscope. Identification was performed based on morphological characters (Kreier 1977). Ehrlichiosis is well known as an important emerging tick-borne disease of mammals having a broad host range. Detection of Ehrlichia organisms in monocytes of a nonhuman primate, the langur, seems to be a first report from Indian subcontinent. The occurrence of disease has been well-documented in human and nonhuman primates from other parts of the globe. Foley et al. (1999) successfully inoculated two Rhesus Macaques (Macaca mulatta) with human granulocytic ehrlichiosis, which was confirmed by polymerase chain reaction (PCR), Western blot and clinical manifestations. Natural Ehrlichia chaffeensis infection in 2 prosimian primate species i.e. Ring-tailed Lemur (Lemur catta) and Ruffed Lemur (Varecia variegata) was documented by Williams et al. (2002) from Duke University Primate Center (U.S.A.). Ring-tailed Lemurs, Blue-eyed Black Lemurs (Eulemur macaco flavifrons) and Black and White Ruffed Lemurs (Varecia variegata variegata) were tested serologically and by PCR assay for detection of tick-borne ehrlichiae and were found positive without showing any clinical manifestations (Yabsley et al. 2004). Rhesus Macaques and Baboons (Papio anubis) were inoculated with Ehrlichia equi, the etiologic agent of equine ehrlichiosis and ehrlichial morulae were evidenced in neutrophils of Rhesus Macaques and Baboons (Lewis et al. 1975). E. chaffeensi and a Venezuelan human Ehrlichia, likely a strain of E. canis, has been isolated from a human (Anderson et al., 1991; Perez et al., 1996). However, inoculation of E. canis by Van Harden and Goosen (1981) did not induce disease in vervet monkeys (Cercopithecus pygerythrus).
[Show abstract][Hide abstract] ABSTRACT: The present communication reports on the kinetics of immunoglobulin isotype response in Fasciola gigantica infected bovine calves. Fifteen Holstein-Friesian cross-bred male calves were assigned to 3 groups (Gr) of 5 calves each and infected with 4-month (Gr-A) and 16-month-old (Gr-B) F. gigantica metacercariae (n=400), respectively, while Gr-C calves served as uninfected control. Infection was terminated by treating the animals with triclabendazole on 28 weeks post-infection (WPI). Sera were collected on 0, 4, 10 and 14 days post-infection (DPI) and subsequently at weekly interval up to 32 WPI. The immunoglobulin isotype response was analyzed by ELISA, using anion exchange purified antigen fraction. An IgG response against F. gigantica infection was evoked by 3 and 2 WPI in animals of Gr-A and Gr-B, respectively with peak antibody response at 13 WPI. Elicitation of an early IgG1 response by 10 and 14 DPI but a delayed IgG2 response at 6 and 4 WPI, in animals of Gr-A and Gr-B, respectively was recorded. An early IgM response was evoked by 10 and 14 DPI and the level peaked at 13 and 12 WPI, with no detectable level at 21 and 15 WPI in animals of Gr-A and Gr-B, respectively. IgA response was elicited at 4 WPI in both the groups and showed the highest titre at 25 and 27 WPI in animals of Gr-A and Gr-B, respectively. Present study indicated an early and predominant response of IgG1, with concurrent expression of delayed and weak IgG2 in calves experimentally infected with F. gigantica.
[Show abstract][Hide abstract] ABSTRACT: Metacercarial antigen of Fasciola gigantica was evaluated for early immunodiagnosis of experimental bovine fasciolosis using ELISA and Western blot. In ELISA, the experimental F. gigantica infection was detected as early as 2 weeks post-infection (WPI). The gradual increasing trend of antibody level was observed from 2 to 7 WPI, followed by a plateau, which was maintained up to 14 WPI. In Western blot, sera from experimentally infected calves recognized one distinct polypeptide of 21 kDa in fractionated metacercarial antigen as early as 10th day post infection. From 2 WPI, more polypeptide bands were reacting. Recognition of these protein bands persisted till the end of the experiment (14 WPI). Cattle sera collected from the field showed 34.5% seroprevalence of fasciolosis by ELISA using MAg. Comparative immunoblot studies of metacercarial antigen with anti-Gigantocotyle explanatum and anti-Paramphistomum epiclitum sera revealed that 21 and 25 kDa polypeptides of metacercarial antigen did not cross-react with any of these sera and appear to be unique to F. gigantica and having the desirable qualities of early and specific immunodiagnosis.
Indian journal of experimental biology 10/2006; 44(9):749-53. · 0.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cathepsin L cysteine proteinase from Fasciola gigantica was evaluated for its potential in the early prepatent detection of this helminth infection in bovine calves. Five cross-bred bovine calves were experimentally infected with 400 metacercariae/calf and evaluated for anti-cathepsin L antibody response. F. gigantica infection in these calves could be detected 4 weeks post-infection using an ELISA, dipstick ELISA and Western blotting with 100% sensitivity. The antigen was also used to detect F. gigantica field infection in cattle, by screening 256 sera of these animals by an ELISA, which demonstrated an overall infection rate of 26.95%. Preliminary studies showed that F. gigantica cathepsin L cysteine proteinase does not cross-react with Paramphistomum epiclitum, Gigantocotyle explanatum and hydatid cyst antigens. However, extensive studies on the cross-reactivity of this antigen with related helminth parasites of cattle and buffaloes are required, before this antigen can be considered suitable for immuno-diagnosis of fasciolosis in these ruminants.