Nelson Marreros

• Doctor of Veterinary Medicine
• Research Associate at Bern University of Applied Sciences

Bovine tuberculosis (BTB) is an infectious disease of livestock and wildlife species that is caused by pathogenic members of the Mycobacterium tuberculosis complex such as Mycobacterium bovis. Due to the introduction of M. bovis-infected bison in the 1920s, BTB is now endemic in wood bison (Bison bison athabascae) population within the Wood Buffalo...

Red deer populations, once extirpated in large parts of Europe, have recovered over the last century in many regions. In Switzerland, primarily inhabiting mountain forests, they have recently started to expand into human-dominated lowland landscapes. To study their habitat selection, we analyzed day- and nighttime positions of 15 GPS-collared red d...

Spirorchiidosis, caused by blood flukes of the genus Spirorchis, is a disease of great concern for the critically endangered European pond turtle (EPT; Emys orbicularis) in Switzerland. The endogenous life cycle of the parasite often leads to systemic inflammatory reactions, thrombosis, and death. Praziquantel (PZQ) is the treatment of choice again...

Background The role of the domestic cat as definitive host for Echinococcus multilocularis and thus in environmental contamination with eggs has not yet been entirely resolved. This study aimed to assess the prevalence of E. multilocularis and other gastrointestinal parasites in Swiss domestic cats and to compare the diagnostic sensitivity of diffe...

An R Shiny App to calculate IC50 and confidence interval.

Trichinellosis is a potentially deadly parasitic zoonosis that is contracted by consuming undercooked infected meat. Reliable detection of infectious Trichinella spp. larvae in meat is therefore pivotal to ensure consumer's safety. The recently authorised PrioCHECK™ Trichinella Alternative Artificial Digestion (AAD) test kit appears promising when...

Alveolar echinococcosis (AE) is a deadly parasitic disease that requires lifelong treatment with albendazole. Development of host immunity is pivotal with regard to the clinical outcome of AE, but its influence on conventional albendazole treatment is unknown. Using T-cell deficient athymic nude mice, we demonstrated that functional immunity is req...

Background: Zoonotic taeniid cestodes are amongst the most important food-borne parasites affecting human health worldwide. Contamination of fresh produce with the eggs of Echinococcus granulosus (s.l.), Echinococcus multilocularis, and some Taenia species pose a potential food safety risk. However, very few studies have attempted to investigate t...

The cover image, by N. Marreros et al., is based on the Original Article Fatal leptospirosis in free-ranging Eurasian beavers (Castor fiber L.), Switzerland, DOI: 10.1111/tbed.12879.

Alveolar echinococcosis (AE) is a lethal disease caused by infection with the metacestode stage of the helminth Echinococcus multilocularis , which develops into a tumor-like mass in susceptible intermediate hosts. The growth potential of this parasite stage is directly linked to the nature of the surrounding periparasitic immune-mediated processes...

Leptospirosis was first diagnosed in free‐ranging Eurasian beavers (Castor fiber L.) in Switzerland in 2010. Pathologic, serologic, molecular and epidemiologic analyses were carried out on 13 animals submitted for necropsy from 2010 through 2014. Typical lesions included alveolar haemorrhages in the lungs, tubular degeneration and interstitial neph...

Infections with helminth parasites can negatively affect performance of dairy cows. Knowledge on infection intensity, spatial distributions and risk factors are key to develop targeted treatment strategies. Canada and most EU countries have conducted large investigations, but respective data for Switzerland were missing. We now performed a bulk tan...

Background Besides acting as definitive hosts for Echinococcus multilocularis, dogs can become infected by the larval form of this parasite and thereby develop life-threatening alveolar echinococcosis (AE). Although AE is a zoonotic disease, most therapeutic and diagnostic approaches have been developed for human patients. In dogs, AE is typically...

Infection with Serratospiculum species was identified in a captive peregrine falcon (Falco peregrinus) in Switzerland. Pathologic and parasitologic examination results revealed generalized severe granulomatous airsacculitis, with intralesional adults, larvae, and eggs of Serratospiculum species. Subsequently, an individual coprological analysis of...

Alveolar echinococcosis (AE) is an emerging zoonotic disease caused by the cestode Echinococcus multilocularis. The secondary infection model of AE is based on intraperitoneal injection of disease-causing metacestodes into the peritoneal cavity of mice, which allows investigations on novel drugs or immunotherapeutical treatment options in vivo. So...

Cows on an alpine pasture were presented with severe signs of vaginitis. To rule out infection with Tritrichomonas foetus, vaginal swabs were taken and real-time PCR based on detection via fluorescence resonance energy transfer (FRET) probes and targeting the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA (rDNA) was performed. P...

Background: Bovine besnoitiosis, caused by the protozoan Besnoitia besnoiti, reduces productivity and fertility of affected herds. Besnoitiosis continues to expand in Europe and no effective control tools are currently available. Experimental models are urgently needed. Herein, we describe for the first time the kinetics of standardised in vitro m...

Background. In Switzerland, leptospirosis is still considered as a travel-associated disease. After the surprising diagnosis of leptospirosis in a patient who was initially suspected as having primary human immunodeficiency virus infection, we recognized that acquisition of leptospirosis occurred through recreational activities and we identified ad...

An outbreak of foot rot occurred in the ibex colony " Vanil Noir " in Switzerland from May to December 2014. This article describes field observations and the analyses carried out on the limbs of 3 animals submitted for postmortem examination. Disease signs observed in the field included lameness, poor body condition and overgrown hooves. Macroscop...

Secondary sexual traits in males of polygynous species are important determinants of reproductive success. It is, however, unknown if and how the development of continuously growing traits at different life-stages is related to reproduction in long-lived male mammals. In this study, we evaluated the relationship of early and late horn growth on soc...

Infections with Mycobacterium bovis and closely related members of the Mycobacterium tuberculosis complex (MTC) are shared between livestock, wildlife and sporadically human beings. Wildlife reservoirs exist worldwide and can interfere with bovine tuberculosis (TB) eradication efforts. The Eurasian wild boar (Sus scrofa) is a MTC maintenance host i...

The acquisition of accurate information on the size of traits in animals is fundamental for the study of animal ecology and evolution and their management. We demonstrate how morphological traits of free-ranging animals can reliably be estimated on very large observation distances of several hundred meters by the use of ordinary digital photographi...

In 2011 and 2012, outbreaks of clinical canine babesiosis were observed in 2 areas of the Swiss Midlands that had no history of this disease so far. In one area, cases of canine babesiosis occurred over 2 consecutive tick seasons. The outbreaks involved 29 dogs, 4 of which died. All dogs were infected with large Babesia sp. as diagnosed in Giemsa-s...

Mycoplasma conjunctivae, the causative agent of infectious keratoconjunctivitis (IKC), was recently detected in asymptomatic Alpine ibex (Capra ibex ibex). This suggested that an external source of infection may not be required for an IKC outbreak in wildlife but might be initiated by healthy carriers, which contradicted previous serologic investig...

Although louping ill affects mainly sheep, a 2011 outbreak in northern Spain occurred among goats. Histopathologic lesions and molecular genetics identified a new strain of louping ill virus, 94% identical to the strain from Britain. Surveillance is needed to minimize risk to domestic and wildlife species and humans.

According to life-history theory age-dependent investments into reproduction are thought to co-vary with survival and growth of animals. In polygynous species, in which size is an important determinant of reproductive success, male reproduction via alternative mating tactics at young age are consequently expected to be the less frequent in species...

To provide baseline parasitological data for health surveillance in free-ranging Alpine ibex (Capra ibex ibex), we assessed the endoparasite population and level of parasitism in apparently healthy ibex. Faecal samples from 148 ibex were collected between 2006 and 2008 in two different Swiss ibex colonies. They were analysed by coprology, including...

In the early 2000s, several colonies of Alpine ibex (Capra ibex ibex) in Switzerland ceased growing or began to decrease. Reproductive problems due to infections with abortive agents might have negatively affected recruitment. We assessed the presence of selected agents of abortion in Alpine ibex by serologic, molecular, and culture techniques and...

Chlamydophila (C.) abortus is the most common infectious abortigenic agent in small domestic ruminants in Switzerland. In contrast, the knowledge about chlamydiae in wild ruminants is scarce. As interactions between livestock and Alpine ibex (Capra i. ibex) occur on alpine pastures, the question raises if wild ruminants could play a role as carrier...

Chlamydophila (C.) abortus is the most common infectious abortigenic agent in small domestic ruminants in Switzerland. In contrast, the knowledge about chlamydiae in wild ruminants is scarce. As interactions between livestock and Alpine ibex (Capra i. ibex) occur on alpine pastures, the question raises if wild ruminants could play a role as carrier...

Mycoplasma conjunctivae is considered the major cause of infectious keratoconjunctivitis (IKC) in Alpine ibex (Capra i. ibex) and chamois (Rupicapra r. rupicapra). While it is known that domestic sheep can act as healthy carriers for M. conjunctivae, this question has not been addressed in wild ungulates so far. In this study, bacteriological inves...