A. Alonso Aguirre

Adrenal and Hematological Responses to Stress in Juvenile Green Turtles (Chelonia mydas) with and without Fibropapillomas

This study reports baseline adrenocortical, hematological, and plasma biochemical values for clinically healthy juvenile green turtles from a discrete population at Kaneohe Bay, island of Oahu, Hawaii. Using a general linear modeling program, we compared mean values for these parameters with mean values of a group afflicted with green turtle fibropapillomas (GTFP). Turtles of similar size classes from both groups were collected under the same conditions in the same study area and season at the same time of the day. Corticosterone, hematological, and enzymatic responses to acute and chronic stress were characterized for each group at four different sampling periods: 0 h (within 2 min of capture), 1 h, 3-4 h, and 24 h postcapture. On the basis of the differences identified between groups and times within a group, we conclude that turtles with GTFP are chronically stressed and immunosuppressed.

EVALUATION OF HAWAIIAN GREEN TURTLES (CHELONIA MYDAS) FOR POTENTIAL PATHOGENS ASSOCIATED WITH FIBROPAPILLOMAS

Thirty-two juvenile green turtles (Chelonia mydas) were captured alive in Kaneohe Bay, Island of Oahu, Hawaii, during September 1991. Ten of the turtles sampled were afflicted with green turtle fibropapillomatosis (GTFP) in varying degrees of severity. Virus isolation attempts were negative in all individuals. Using nasopharyngeal and cloacal swabs, we isolated 28 Gram negative bacteria, five Gram positive cocci, Bacillus spp., and diphtheroids. The most common isolates included Pseudomonas fluorescens (68%), P. putrefaciens (66%), Vibrio alginolyticus (50%), non-hemolytic Streptococcus (50%), V. damsela (47%), and V. fluvialis (47%). Chlamydial antigen was detected in four of the turtles sampled. The primary lesions in animals with GTFP were hyperplasia of squamous epithelial cells and mesodermal proliferation with a marked degree of orthokeratotic hyperkeratosis. Mites, leeches, and other organisms were associated with the surface of papilloma lesions. The etiologic agent of GTFP was not isolated.

SPIRORCHIDIASIS AND FIBROPAPILLOMATOSIS IN GREEN TURTLES FROM THE HAWAIIAN ISLANDS

Pathologic examination of green turtles (Chelonia mydas) from the Hawaiian Islands (USA) was performed to determine the primary cause of mortality. Lesions were associated with fibropapillomatosis (FP) and/or spirorchidiasis (SP) in 16 of 17 green turtles examined. Gross lesions included moderate to severe emaciation, lobulated fibropapillomas of different size classes, serous atrophy of fat, and edema of subcutaneous tissue and muscle. Anasarca, hydropericardium and pulmonary edema were common findings. The neoplastic lesions observed in the gastrointestinal tract, lungs, liver, and kidneys of 29% of turtles examined were histologically characterized as fibromas. A generalized thickening and hardening of major vessels and thrombosis with partial or complete lumen occlusion were observed in turtles with FP and SP. Histologically, lymphoplasmocytic endarteritis was observed in vessels of turtles with both conditions. Multifocal granulomas were associated with trematode ova in the parenchyrna of most organs of all turtles with FP and SP. Spirorchidiasis and FP were considered the primary causes of mortality in the turtles examined. Further studies should focus on the pathogenic interaction of both conditions and their synergism as debilitating and fatal diseases in this threatened species.

DESCRIPTIVE EPIDEMIOLOGY OF ROE DEER MORTALITY IN SWEDEN

A retrospective epidemiologic study was conducted to examine causes of mortality of 985 wild roe deer (Capreolus capreolus) submitted to the National Veterinary Institute (SVA; Uppsala, Sweden) from January 1986 to December 1995. Age, sex, body condition, and geographic distribution as related to disease conditions are reported herein. The most common causes of mortality in roe deer were trauma (19%), winter starvation (18%), gastritis/enteritis (15%), bacterial infections (11%), parasitic infection (11%), systemic diseases (11%), neoplasia (2%), congenital disorders (1%), and miscellaneous causes (6%). Cause of death was not determined in 6% of the cases. The distribution of causes of death reported in this study differ from previous works in Sweden in that infectious and parasitic diseases were more common than winter starvation. The pathologic findings in studies like this do not necessarily represent what is occurring in the natural environment, but they do provide a good indication of distribution of diseases over time as well as age and sex structure in relation to disease conditions. Further research and more detailed studies are in progress to better understand specific mortality factors as well as etiologies of certain described diseases in roe deer in Sweden.

Serologic Survey for Selected Arboviruses and Other Potential Pathogens in Wildlife from Mexico

During 1988 and 1989, a serologic survey of wildlife was conducted in northeastern Mexico to determine the presence, prevalence, and distribution of arboviruses and other selected disease agents. Eighty mammal specimens were tested. Antibodies to vesicular stomatitis-Indiana, Venezuelan equine encephalitis–Mena II, Rio Grande virus, and vesicular stomatitis-New Jersey were detected predominately in small mammals. Deer and mouflon (Ovis musimon) had antibodies to bluetongue and epizootic hemorrhagic disease. Two species had serologic evidence of recent exposure to Francisella tularensis. A white-tailed deer (Odocoileus virginianus) had antibodies to Anaplasma marginale. All specimens tested for antibodies against Yersinia pestis and Brucella abortus were negative. Sera from 315 birds were tested for antibody against five equine encephalitis viruses and six avian pathogens. During 1988, antibodies to Venezuelan equine encephalitis–Mena II, Venezuelan equine encephalitis-TC83, St. Louis encephalitis, eastern equine encephalitis, and western equine encephalitis were detected in birds of several species. Antibodies to Pasteurella multocida and Newcastle disease virus were also detected. Birds from five species presented antibodies to Mycoplasma meleagridis. Specimens tested for M. gallisepticum, M. synoviae, and Chlamydia psittaci were negative. To the best of our knowledge, this survey represents the first serologic evidence of bluetongue, Cache Valley virus, epizootic hemorrhagic disease, Jamestown Canyon virus, vesicular stomatitis–Indiana, vesicular stomatitis–New Jersey, Rio Grande virus, and tularemia reported among wildlife in Mexico.

Revision of Hemoproteid Genera and Description and Redescription of Two Species of Chelonian Hemoproteid Parasites

Abstract:  Pigmented hemosporidian parasites that do not exhibit erthyrocytic schizogony, and infect birds, chelonians, and squamates, have been classified in various genera over time. These classifications have reflected vertebrate hosts, insect vectors, and variations in morphology and life history observed in representative species. Side-necked turtles (Podocnemis spp.) from the Peruvian Amazon were screened for hemoparasites and 2 species of hemosporid parasites infecting these hosts were observed. Molecular phylogenetic analysis of these new isolates, along with parasites from lizards, a snake, and a variety of Haemoproteus species from birds from both the Haemoproteus and Parahaemoproteus subgenera, strongly support the separation of the non-avian parasites into a separate genus. The name with precedent for this group is Haemocystidium Castellani and Willey 1909, and we propose that subgeneric classification of Haemocystidium and Simondia be applied to parasites of squamates and chelonians, respectively. We offer a description of Haemocystidium (Simondia) pacayae n. sp. and a redescription of Haemocystidium (Simondia) peltocephali (Lainson and Naiff 1998, n. comb.) Morphologically, the parasites are quite similar, with H. pacayae slightly more elongated than H. peltocephali. The discovery and identification of parasite species is urgent, especially in endangered species and wildlife inhabiting rapidly declining ecosystems such as the Amazon.

Detection by ELISA of circulating anti-blood fluke (Carettacola, Hapalotrema, and Learedius) immunoglobulins in Hawaiian green turtles (Chelonia mydas)

An enzyme-linked immunosorbent assay (ELISA) is described utilizing the surface glycocalyx crude antigen of adult blood trematodes Learedius learedi, Hapalotrema dorsopora, and Carettacola hawaiiensis, for the detection of circulating antibodies (Ab) in Hawaiian green turtles (Chelonia mydas) naturally infected with the parasites and with or without green turtle fibropapillomatosis (GTFP). A concentration of 10.0 micrograms/ml of antigen was optimal in terms of test specificity and sensitivity. A direct ELISA with anti-reptilian/amphibian phosphatase-labeled IgG identified C. mydas Ab at a dilution of 1/12,800. Utilizing indirect ELISA, it was possible to detect Ab to blood flukes at a dilution of 1/3,200. The gross lesions and histopathology were typical for cardiovascular spirorchidiasis in C. mydas. No significant relationship was found between the size of turtles and the degree of GTFP severity. Forty-seven of 59 (80%) samples, from 5 sites, gave a positive ELISA reaction; 6 of the 47 (13%) specimens gave significantly (P < 0.001) higher absorbance values, with 5 from the same location. All 12 (20%) ELISA-negative turtles originated from 1 site, and the absorbance values of the 41 animals from this location were significantly lower (P < 0.015) when compared with the other 4 sites. The proposed assay is fast, has the feature of visual scoring, and can be used for determination of exposure of C. mydas to the spirorchid trematodes.

BLOOD PARASITES OF SOME BIRDS FROM NORTHEASTERN MEXICO

A total of 196 birds of 31 species from 15 families from northeastern Mexico was examined for blood parasites; 25 birds (12.8%) of 11 species harbored 1 or more species of hematozoans. Species of Haemoproteus accounted for half of the total infections encountered. Leucocytozoon simondi was found in 2 Mexico ducks (Anas diazi) and this represents the first record of the transmission of this parasite in Mexico. The results of this survey were compared with those obtained nearly 50 yr ago from a survey of birds from the same general area; prevalence in both samples was similar, despite the change to a more agricultural environment over this period.

Cloacal flora isolated from wild black-bellied whistling ducks (Dendrocygna autumnalis) in Laguna La Nacha, Mexico.

Cloacal swabs from 110 adult black-bellied whistling ducks trapped at Laguna La Nacha, Tamaulipas, Mexico, were cultured to determine the prevalence of normal and potentially pathogenic bacteria. Twenty-five gram-negative enterobacteria and four gram-positive cocci were isolated. The most common isolates included Escherichia coli (54%), Staphylococcus spp. (29%), Streptococcus spp. (22%), Aeromonas hydrophila (15%) Enterobacter cloacae (14%), and Micrococcus sp. (14%). The implications of whistling ducks as possible reservoirs of pathogenic bacteria are discussed.

Experimental inoculation of three arboviruses in black-bellied whistling ducks (Dendrocygna autumnalis).

Wild-caught, immature black-bellied whistling ducks (Dendrocygna autumnalis) were inoculated with eastern equine encephalitis (EEE), St. Louis encephalitis (SLE), or western equine encephalitis (WEE) virus. Susceptibility, duration and titer of viremia, and antibody response to these arboviruses were determined. Birds from all inoculated groups became viremic. Higher virus titers occurred in the EEE group but overall mean titers were not significantly different among experimental groups. All birds inoculated with EEE and SLE viruses developed antibodies, and six of seven ducks receiving WEE virus were seropositive. All seropositive ducks had antibodies for at least 59 days, when the study was terminated. The EEE group had significantly more seropositive ducks during more days than the WEE and SLE groups. Geometric mean antibody titers were significantly smaller in the WEE group when compared to the EEE and SLE groups. Control ducks did not develop viremia or antibodies. Gross and histopathologic lesions compatible with viral encephalitis were absent in all of nine ducks necropsied. Black-bellied whistling ducks can develop low and short-term levels of viremia sufficient to infect mosquitoes, but probably cannot contribute significantly to the transmission of EEE and SLE. They may serve as good indicators of virus activity.