Marine turtles life cycle it’s very complex, alternating between reproduction areas and feeding and/or development areas, finding within the last areas, individuals from different nesting beaches (López-Mendilaharsu et al., 2006).

The Western South Atlantic (ASO) is an area of high activity for these turtles (González Carman et al., 2011) and particularly the Uruguayan coast is an important feeding and development area and migration corridor between areas of ASO for juveniles of C. mydas (Estrades et al., 2007).

Different diseases affecting sea turtles directly influence at their survival. Recently, a disease called fibropapillomatosis, it has become important. Another of the most common diseases of sea turtles is about infestation by parasites .

Parasitism by Ozobranchus branchiatus and Ozobranchus margoi can kill the host by anemia and skin lesions (Peralta, 2003).

Studies implicate this ecto-parasitas as possible mechanical vectors of transmission of the sea turtle’s herpes virus (Greenblatt, et al. 2004).

The life cycle of these leeches turtle is unknown, including whether it may or may not survive in the absence of its host (Mc Gowin et al., 2011).

Because the exposed above, the aim of this research is:

INTRODUCTION

Determine the association of the prevalence of parasites with attributes of the host, like the body mass index and biometry; and environmental variables, like site and season of capture.

Study area

Campaigns

Sampled individual

Features relieved

Preserved in formalin 4%

Identified (stereoscopic microscope - Sawyer, 1975)

Weight (Kg)

Curved carapace length (LCC)

Curved carapace straight (ACC)

Tumor presence and leeches

Data analyses

Descriptive analyzes

Figure 1 – Study area: Marine Protected Area “Cerro Verde e Islas de La Coronilla”, Uruguay.

AIM

METHODOLOGY

Prevalence of infection by Ozobranchus spp.

Leeches shown an inverse pattern in their prevalence of infection

Currently, Cheng-Tsung Tseng (2011) proposed that O. branchiatus has no swimming ability, but is able to trace sea ground and infect turtles when resting on the seabed. Due to their morphological similarities, O. margoi could present these same capabilities.

Due the intensity of infection of O. margoi is highest during the first months of the season, its possible that this species parasitizes turtles when they still found in low densities in the area, so O. margoi could have a more efficient strategy of infestation. It is possible that both species of parasites possess different reproductive cycles.

Is known that the optimum water temperature for incubation and hatching of eggs for O. branchiatus is below 25 ° C.

The development of O. margoi it could occur by early the warm season, when the surface temperature is colder towards the end of it, thus explaining the different temporal patterns recorded for these species in this study.

Since the analysis of variation within and between-season show no major changes in the prevalence and intensity of infection throughout the years, and if they show a similar seasonal pattern within each

season, leeches of genus Ozobranchus could be not a problem to the Cerro Verde's sea turtles population, in Uruguay, and probably the parasite load could be constant within this population. What is more, this population could have a dynamic host-parasite stable, with certain parasitism patterns, within

each season and for each species of parasite.

Table 1. Generalized linear model (GLM) using a multivariable logistic regression to describe factors associated with the prevalence of parasitism of all the leeches in juveniles of Chelonia mydas.

NOTE: SE = standard error; P = P value of the test; BMI = body mass index; Year = variation of parasitism between seasons; I (year ^ 2) = the probability of infection by a species throughout the seasons; Variation of parasitism Month = January to April of each season.

Table 2. Generalized linear model (GLM) using a multivariable logistic regression to describe factors associated with the prevalence of parasitism in O. margoi juveniles Chelonia mydas.

NOTE: SE = standard error; P = p-value of the test; O.branchiatus = presence of another parasite; Weight = weight of the turtle; Year = variation of parasitism between seasons; Month = variation in the intensity of parasitism from January to April of each season; I (mm ^ 2) = probability of infestation by species over the months.

Table 3. Generalized linear model (GLM) using a multivariable logistic regression to describe factors associated with the prevalence of parasitism in O. branchiatus juveniles Chelonia mydas.

NOTE: SE = standard error; P = p-value of the test; O. margoi = presence of another parasite; IMC = body mass index; Año (year) = variation of parasitism between seasons; I (year ^ 2) = probability of infestation by a species throughout the seasons; Mes (month) = Variation of parasitism from January to April every season.

PREVALENCE OF PARASITISM OF THE SPECIES Ozobranchus branchiatus AND O. margoi IN JUVENILE GREEN TURTLE POPULATION IN CERRO VERDE,

URUGUAYMaría Silvina Bevilacqua1; Luciana Alonso2 y Pablo M. Beldomenico3, 4, 5

1 – Fac. de Humanidades y Ciencias, Univ. Nacional del Litoral, CU, Paraje El Pozo s/n. Santa Fe, Argentina. E-mail: mariasilvinabevilacqua@gmail.com2 - Karumbé, Avda. Gral Rivera 3245, CP 11600, Montevideo.

3 - Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral (FCV-UNL), R. P. Kreder 2805, Esperanza, Santa Fe, Argentina. 4 - Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.

5 - Global Health Program, Wildlife Conservation Society, Bronx, NY, USA.

RESULTS AND DISCUSSION

Leeches

Ecological parasitism descriptors: mean parasite abundance, mean intensity and prevalence of infection.Multivariate analyses (logistic regression model)

The Akaike Information Criterion (AIC)

To determine association between prevalence infection, host's attributes and environmental variables

To select the model

Intentional capture and stranded individuals

January to April, from 2007 to 2010

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Prevalence of infection by O. margoi

In presence of the other parasite (O. branchiatus) it is more probably the presence of O. margoi

Heavier animals were more susceptible to infection by this species of leech (p<0,05).

The prevalence of infection by O. margoi tends to decrease from January to April.

Prevalence of infection by O. branchiatus

In the presence of O. margoi it is more likely to find this species

Hosts with higher BMI has a higher prevalence of infection with O. branchiatus.

Also, the probability to be infected with O. branchiatus increases since January to April.

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O. branchiatus

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(Figure 1)

The probability to be infected with leeches increases when the BMI of turtles increases (p < 0,05).

The probability to be infected with leeches increases between January and April in each season (p < 0,05).

Given its direct development, infection with leeches could depends on the probability of direct transmission to another host.

The increase prevalence of infection with individuals of genus Ozobranchus from January to April each season, could be associated with the coincidence of the reproductive period of parasites with increasing relative abundance of sea turtles in the area and his congregation on rocky points, increasing the probability that the leeches find a suitable host to infect.

(Table 1 and Figure 2)

(Table 2 and Figure 3)

(Table 3 and Figure 4)

Figure 3. Prevalence of infection by O. margoi bye campaigns and by month

Figure 4. Prevalence of infection by O. branchiatus bye campaign and by month.

Figure 2. Prevalence of infection by Ozobranchs spp. bye campaign and by month

CONCLUSION

leeches

leeches eggs