Do superspreaders generate new superspreaders?: A hypothesis to explain the propagation pattern of COVID-19

The current global propagation of COVID-19 is heterogeneous, with slow transmission continuing in many countries and exponential propagation in others, where the time that it took for the explosive spread to begin varied greatly. It is proposed that this could be explained by cascading superspreading events, in which new infections caused by a superspreader are more likely to be highly infectious. The mechanism suggested for this is related to viral loads. Exposure to high viral loads may result in high-intensity infection, which exposes new cases to high viral loads. This notion is supported by experimental veterinary research.Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentin

The vicious circle and infection intensity: The case of Trypanosoma microti in field vole populations

Objective: In natural populations, infection and condition may act synergistically to trigger a vicious circle: poor condition predisposes to host infections, which further reduce condition, and so on. If this vicious circle originates from a reduced resistance to infection, it will not only result in greater proneness to becoming infected of those that are in poorer condition, but it may also cause infections of higher intensity. Here, we investigate the temporal relationship between host condition and intensity of infection by a specific pathogen using as a system the dynamics of the protozoan Trypanosoma microti in field vole (Microtus agrestis) populations. Methods and results: With two years of longitudinal data from three monthly-sampled populations, we evaluated if individuals acquiring a high intensity of infection previously had lower haematological indicators of condition (red blood cells [RBCs] and lymphocyte counts) than those that acquired lower infection intensities. Also, the association of these indicators with past and present trypanosome blood levels was investigated. The individuals that developed high levels of parasitaemia were those that previously had low lymphocyte counts. Greater intensity of infection corresponded with lower RBCs only in low to moderate weight females, and no effect of intensity of infection on lymphocyte counts was observed. However, delayed effects of high trypanosome intensity were seen on both RBCs and lymphocytes. Conclusions: The vicious circle may also result in high infection intensity: individuals in poor condition are not only more likely to become infected by one pathogen; they may also be the most important source of infection for that and for other pathogens, and thus key protagonists for parasite dynamics.Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Telfer, Sandra. University of Liverpool; Reino UnidoFil: Gebert, Stephanie. University of Liverpool; Reino UnidoFil: Lukomski, Lukasz. University of Liverpool; Reino UnidoFil: Bennett, Malcolm. University of Liverpool; Reino UnidoFil: Begon, Michael. University of Liverpool; Reino Unid

Veterinary sciences and one health approach in pandemic times

Las Ciencias Veterinarias surgieron y se desarrollaron para atender intereses y demandas de la sociedad en los que resultaba relevante la salud animal. En los tiempos en los que Claude Bourgelat fundaba las primeras escuelas de Veterinaria en Francia (Lyon en 1761; Alfort en 1764), la necesidad que impulsó esa iniciativa fue la de atender problemas sanitarios de especies animales que cumplían roles de gran importancia para la sociedad: los equinos y los bovinos. En esos inicios de la disciplina, la visión de Bourgelat fue pionera y de avanzada, adoptando aproximaciones que son impulsadas por las disciplinas científicas en la actualidad, como son los enfoques comparados, interdisciplinarios e integrativos (Wake, 2003).Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentin

Experimental evidence of parasite-induced behavioural alterations modulated by food availability in wild capuchin monkeys

In disease dynamics, host behaviour can both determine the quantity of parasites a host is exposed to, and be a consequence of infection. Observational and experimental studies in non-human primates have consistently found that parasitic infections result in less movement and reduced foraging, which was interpreted as an adaptive response of the host to counter infection. Variation in host nutritional condition may add complexity to the infection-behaviour relationship, and its influence may shed light on its significance. To experimentally evaluate how host activity and social relationships are affected by the interaction of parasitism and nutrition, during two years we manipulated food availability by provisioning bananas, and helminth infections by applying antiparasitic drugs, in two groups of wild black capuchin monkeys (Sapajus nigritus) in Iguazú National Park, Argentina. We collected faecal samples to determine the intensity of helminthic infections, as well as data on behaviour and social proximity. Individuals with unmanipulated helminth burdens foraged less than dewormed individuals only when food provisioning was low. Resting time was increased when capuchins were highly provisioned, but it did not vary according to the antiparasitic treatment. Proximity associations to other group members were not affected by the antiparasitic treatment. This is the first experimental evidence of a modulating effect of food availability on the influence of helminth infection on activity in wild primates. The findings are more consistent with an impact on host behaviour due to the debilitating effect caused by parasites than with an adaptive response to help fight infections.Fil: Agostini, Ilaria. Administración de Parques Nacionales. Parque Nacional "Nahuel Huapi"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Vanderhoeven, Ezequiel Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Pfoh, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Tiddi, Barbara. Bristol Zoological Society; Reino UnidoFil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; Argentin

Ecoepidemiology of Rickettsia parkeri in the Paraná Delta, Argentina

Background: In South America, several cases of human rickettsiosis caused by Rickettsia parkeri were documented in Uruguay, southern Brazil and the Paraná River delta of Argentina. There, the main tick vector is Amblyomma triste. Adults of A. triste seek blood meals from large mammals (including humans), whereas immature stages feed on small rodents.Methods & Materials: With the aim of shedding light on the ecology of this emerging disease, we conducted field studies at sites of the Paraná River delta, which consisted of systematic collection of ticks and blood samples from rodents (Fig. 2) and cattle, and also questing ticks from the vegetation. Sampling sessions were carried out monthly during 2011 and 2012 at 16 points that differed in their exposure to cattle and vegetation type (natural or implanted forest).Results: Prevalence of infection in adult questing ticks was high (20.4%). Interestingly, the distribution of R. parkeri infection intensity observed in A. triste ticks was distinctly bimodal, with approximately 60% of the infected ticks presenting high rickettsial loads (Fig. 3). Questing ticks were more frequently found in natural grasslands than in implanted forests, and prevalence of infection were greater in those from grasslands (26%) than in forested areas (8.3%). The dominant rodent species were Akodon azarae and Oxymycterus rufus. In both, the seroprevalence to R. parkeri was greater in those captured in grasslands than in implanted forests. The presence of cattle had a significant positive effect on the burdens of ticks on rodents and the abundance of questing ticks in the vegetation. Most cattle (90%) were seropositive, and the seasonality of the titres of antibodies against R. parkeri matched that of the tick infestation on cattle.Conclusion: The risk of human exposure to R. parkeri infected ticks in the Paraná River delta is high. Our results suggest that the silvopastoral activities that are on the rise in the region affect the dynamics of infection of R. parkeri. Cattle appear to favour the occurrence of the pathogen, whereas forestation seems to reduce it.Fil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Colombo, V.. No especifíca;Fil: Monje, Lucas Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Antoniazzi, Leandro Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina17th International Congress on Infectious DiseasesHyderabadIndiaInternational Society for Infectious Disease

Primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus) en el nordeste de Argentina

Primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus) en el Nordeste de Argentina. Los parásitos juegan un rol importante en la ecología de los primates. Aunque los parásitos gastrointestinales han sido investigados en varios taxa de primates, todavía existe un vacío de información para algunas especies. Aquí reportamos los resultados del primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus), una especie endémica del Bosque Atlántico. Durante tres inviernos y un verano, colectamos 665 muestras fecales de 44 individuos identificados pertenecientes a dos grupos de monos caí en el Parque Nacional Iguazú en el Nordeste de Argentina, para realizar análisis parasitológicos. En total identificamos ocho helmintos: Filariopsis sp., Strongyloides sp., Trichuris sp., Ascaris sp., un Subuluridae, un Spiruridae, un cestode Hymenolepididae y un Trematode indeterminado. Hymenolepididae (25-42%), Filariopsis sp. (15-42%) y Strongyloides sp. (11-27%) fueron los parásitos más prevalentes independientemente del año y la estación. En promedio, los monos caí infectados presentaron entre 1.12-1.26 taxa de helmintos. La comunidad de parásitos que encontramos presenta similitudes con la de otros Cebidae.Parasites play an important role in primate ecology. Although gastrointestinal parasites have beensurveyed in several primate taxa, there is still a substantial paucity of data for some species. Here we report thefirst coprological survey of helminths in a primate species, the wild black capuchin monkey (Sapajus nigritus),which is endemic to the Atlantic Forest. During three winters and one summer, we collected 665 faecal samplesfrom 44 identified individuals of two capuchin groups in Iguazú National Park, NE Argentina, for parasitologicalanalysis. Overall, we identified eight helminths: Filariopsis sp., Strongyloides sp., Trichuris sp., Ascaris sp.,a Subuluridae, a Physalopteridae, a Hymenolepididae cestode, and an undetermined Trematode. The Hymenolepididae(25-42%), Filariopsis sp. (15-42%), and Strongyloides sp. (11-27%) were the most prevalent parasitesregardless of the survey year, group and season. On average, infected capuchins harboured 1.12-1.26 parasitetaxa. The parasite community observed in the black capuchin monkeys resembled those found in other Cebidae.Fil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Vanderhoeven, Ezequiel Andres. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Beldomenico, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Ciencias Veterinarias del Litoral; Argentina. Laboratorio de Ecología de Enfermedades; ArgentinaFil: Pfoh, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Notarnicola, Juliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

Primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus) en el nordeste de Argentina

Primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus) en el Nordeste de Argentina. Los parásitos juegan un rol importante en la ecología de los primates. Aunque los parásitos gastrointestinales han sido investigados en varios taxa de primates, todavía existe un vacío de información para algunas especies. Aquí reportamos los resultados del primer estudio coprológico de helmintos en una población silvestre de monos caí (Sapajus nigritus), una especie endémica del Bosque Atlántico. Durante tres inviernos y un verano, colectamos 665 muestras fecales de 44 individuos identificados pertenecientes a dos grupos de monos caí en el Parque Nacional Iguazú en el Nordeste de Argentina, para realizar análisis parasitológicos. En total identificamos ocho helmintos: Filariopsis sp., Strongyloides sp., Trichuris sp., Ascaris sp., un Subuluridae, un Spiruridae, un cestode Hymenolepididae y un Trematode indeterminado. Hymenolepididae (25-42%), Filariopsis sp. (15-42%) y Strongyloides sp. (11-27%) fueron los parásitos más prevalentes independientemente del año y la estación. En promedio, los monos caí infectados presentaron entre 1.12-1.26 taxa de helmintos. La comunidad de parásitos que encontramos presenta similitudes con la de otros Cebidae.Parasites play an important role in primate ecology. Although gastrointestinal parasites have beensurveyed in several primate taxa, there is still a substantial paucity of data for some species. Here we report thefirst coprological survey of helminths in a primate species, the wild black capuchin monkey (Sapajus nigritus),which is endemic to the Atlantic Forest. During three winters and one summer, we collected 665 faecal samplesfrom 44 identified individuals of two capuchin groups in Iguazú National Park, NE Argentina, for parasitologicalanalysis. Overall, we identified eight helminths: Filariopsis sp., Strongyloides sp., Trichuris sp., Ascaris sp.,a Subuluridae, a Physalopteridae, a Hymenolepididae cestode, and an undetermined Trematode. The Hymenolepididae(25-42%), Filariopsis sp. (15-42%), and Strongyloides sp. (11-27%) were the most prevalent parasitesregardless of the survey year, group and season. On average, infected capuchins harboured 1.12-1.26 parasitetaxa. The parasite community observed in the black capuchin monkeys resembled those found in other Cebidae.Facultad de Ciencias Naturales y MuseoConsejo Nacional de Investigaciones Científicas y Técnica

Host-parasite biology in the real world: the field voles of Kielder

Peer reviewedPublisher PD

FIRST REPORT OF MYIASIS CAUSED BY PHILORNIS (DIPTERA: MUSCIDAE) IN CACICUS SOLITARIUS (PASSERIFORME: ICTERIDAE) IN CENTRAL ARGENTINA

In January 2016, one Cacicus solitarius bird nestling was found parasitized by subcutaneous larvae in a protected forest of central Argentina. Some larvae were removed from the nestling and reared under laboratory conditions. Using morphological characteristics, the adult flies that emerged were identified as belonging to the Philornis torquans complex. Molecular analysis of the specimens showed identical ITS2 sequences from those previously reported for Philornis flies from Misiones province, in northeastern Argentina. This study presents the first documented association between Philornis and C. solitarius and the first record of the “P. torquans complex genotype Misiones” in central Argentina

Poor condition and infection: a vicious circle in natural populations

Pathogens may be important for host population dynamics, as they can be a proximate cause of morbidity and mortality. Infection dynamics, in turn, may be dependent on the underlying condition of hosts. There is a clear potential for synergy between infection and condition: poor condition predisposes to host infections, which further reduce condition and so on. To provide empirical data that support this notion, we measured haematological indicators of infection (neutrophils and monocytes) and condition (red blood cells (RBCs) and lymphocytes) in field voles from three populations sampled monthly for 2 years. Mixed-effect models were developed to evaluate two hypotheses, (i) that individuals with low lymphocyte and/or RBC levels are more prone to show elevated haematological indicators of infection when re-sampled four weeks later, and (ii) that a decline in indicators of condition is likely to follow the development of monocytosis or neutrophilia. We found that individuals with low RBC and lymphocyte counts had increased probabilities of developing monocytosis and higher increments in neutrophils, and that high indices of infection (neutrophilia and monocytosis) were generally followed by a declining tendency in the indicators of condition (RBCs and lymphocytes). The vicious circle that these results describe suggests that while pathogens overall may be more important in wildlife dynamics than has previously been appreciated, specific pathogens are likely to play their part as elements of an interactive web rather than independent entities