Study of the relationship between Toxoplasma gondii infection and food source in seagull chicks from breeding areas from Spain

Authors: CABEZON, OSCAR - Autonomous University Of Barcelona; CERDA, CUELLAR - Autonomous University Of Barcelona; MORERA, VIRGINIA - Autonomous University Of Barcelona; BOCANEGRA, IGNACIO - Universidad De Cordoba; GONZALEZ-SOLIS, JACOB - Autonomous University Of Barcelona; RIBAS, MARIA - Autonomous University Of Barcelona; BLANCH-LAZARO, BERTA - Autonomous University Of Barcelona; FERNANDEZ-AGUILAR, XAVIER - Autonomous University Of Barcelona; ANTILLES, NOELIA - Autonomous University Of Barcelona; LOPEZ-SORIA, SERGIO - Autonomous University Of Barcelona; LORCA-ORO, CRISTINA - Autonomous University Of Barcelona; Dubey, Jitender; ALMERIA, SONIA - Autonomous University Of Barcelona

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2016
Publication Date: 3/14/2016
Citation: Cabezon, O., Cerda, C., Morera, V., Bocanegra, I., Gonzalez-Solis, J., Ribas, M.P., Blanch-Lazaro, B., Fernandez-Aguilar, X., Antilles, N., Lopez-Soria, S., Lorca-Oro, C., Dubey, J.P., Almeria, S. 2016. Study of the relationship between Toxoplasma gondii infection and food source in seagull chicks from breeding areas from Spain. PLoS One. 11(30):1-11.

Interpretive Summary: Toxoplasma gondii, an obligate, single-celled, protozoan parasite continues to be a major zoonotic health concern in human and veterinary medicine because it is capable of infecting any warm-blooded vertebrate intermediate host. As the definitive host, cats are fundamental in the epidemiology of toxoplasmosis. Millions of oocysts can be excreted in the feces of a single cat and oocysts can survive outdoors for months. This study should be of interest veterinarians and public health workers. Many aspects of this parasite transmission are unknown, including the possibility of transmission to remote areas without cats. Among birds, scavenging species regularly feeding on refuse dumps and sewage water, such as some seagulls, are good candidates to study their epidemiological importance in Toxoplasma infection, but have rarely been studied. Exploring the spread of T. gondii in wild birds and possible links with opportunistic feeding behavior can help understanding the role of birds in maintaining and disseminating parasites over large geographical areas. In the present study the authors found T. gondii antibodies in 21% of 525 sea gulls in Spain. The results will be of interest to biologists, veterinarians, and parasitologists.

Technical Abstract: Understanding the spread of Toxoplasma gondii (T. gondii) in wild birds, particularly in those with opportunistic feeding behavior, is of interest for elucidating the epidemiological involvement of these birds in the maintenance and dissemination of the parasite. Sera from 525 seagull chicks from 6 breeding areas in Spain from Yellow-legged gull (Larus michahellis) and Audouin´s gull (L. audouinii) were tested using the modified agglutination test (MAT) for the presence of antibodies against T. gondii. Since maternal antibody concentration decreases with age in seabird nestlings, we estimated the age of chicks from bill length. In yellow-legged gulls bill growth is known to approach linearity from the first to the fifth week following the relationship: age (days)=bill length (mm)*0.963–22.34 [15], resulting in a chick age ranged from 4 to 30 days. Food intake origin of the seagull chicks was evaluated using stable isotope analyses from growing scapular feathers. The overall seroprevalence was 21.0% (IC95% 17.5-24.4). A generalized estimating equations model showed that the main risk factors associated to T. gondii seroprevalence were food source and year. Year differences could indicate fluctuating rates of exposure of seagull chicks to T. gondii. Freshwater food origin was related to the highest seroprevalence levels, followed by marine food origin. These results reinforce the hypothesis that freshwater and sewages are important routes of dispersion of T. gondii. Seroprevalence was not related to body condition indexes or age. This study is the first report of T. gondii antibodies in Yellow-legged and Audouin´s gulls, thereby extending the range of intermediate hosts for this parasite and improving the knowledge of the epidemiology of T. gondii.