Biology subjects

Vanden Broecke, B.

Publications and source records attributed to Vanden Broecke, B..

7 recordsLinked to original sources

bioRxiv2025

Linking host personality and parasitic infection: a meta-analysis

Animal personality and parasite infections are key forces shaping the ecology and evolution of natural populations. Personality traits--such as activity, exploration, and boldness--shape how individuals interact with their environment and conspecifics, influencing both their exposure and susceptibility to parasite infection. In turn, parasites can impact host fitness and energy allocation, and may modify host behaviour either through manipulations to enhance transmission or as consequences of energetic trade-offs associated with mounting an immune response. Despite growing interest in the interplay between behaviour and infection, the overall directionality and consistency of personality-parasite relationships remain unclear. This relationship is further modulated by ecological and biological factors, such as parasite type (e.g. micro-, ecto-, or endoparasites) and host type (e.g. intermediate versus definitive), which can influence both infection risk and the nature of behavioural responses. To disentangle these effects, we performed a meta-analysis of 226 effect sizes across 80 studies, assessing (i) the impact of experimental infections on host personality traits, and (ii) the correlation between personality and infection status in observational studies of wild populations--while accounting for variation in parasite groups and host roles. In experimental studies, infected hosts exhibited significantly reduced levels of activity and exploration, while effects on boldness and aggressiveness were non-significant. These findings suggest that infection imposes energetic costs that suppress behaviours requiring sustained effort, such as movement and exploration. Conversely, observational studies showed a positive association between activity-exploration and infection probability, likely reflecting greater exposure of more active individuals to parasites via increased interaction with conspecifics or contaminated environments. Meta-regression analyses further revealed that parasite type and host role modulate personality-infection dynamics. In experimental studies, microparasites were associated with reduced boldness and activity-exploration, while endoparasites led to reduced activity- exploration--particularly in intermediate hosts. Notably, hosts showed significant behavioural suppression in experimental contexts, but not in observational studies, potentially indicating that behaviourally tolerant individuals are favoured in natural environments where personality traits relate directly to fitness. Together, these findings underscore the importance of ecological context and study design in interpreting personality-parasite associations. Experimental infections tend to reveal the physiological costs of infection, while observational studies highlight behavioural traits that modulate infection risk. By integrating data across host types, parasite groups, and methodological approaches, our meta-analysis provides a more comprehensive understanding of how personality and infection interact. These insights contribute to a broader effort to link behavioural ecology with disease ecology, clarifying how individual variation in behaviour shapes--and is shaped by--host-parasite dynamics.

animal behavior and cognition↗

bioRxiv2025

Efficiency of Anthelmintic Treatment and Its Effect on Microparasite Dynamics in Wild Mastomys natalensis

Co-infections between helminths and microparasites can influence disease dynamics with potential public health implications. However, establishing clear cause-and-effect relationships from natural populations remains challenging. One approach to address this is through perturbation experiments, where a specific parasite is selectively reduced to directly observe its impact on co-infecting parasites. While such experiments have been conducted in wild rodent populations, they have not yet been explored in Africa, despite the continents importance for emerging infectious diseases and zoonoses. In this study, we investigated potential helminth-microparasite interactions in wild Mastomys natalensis in Tanzania by using anthelmintics to reduce helminth infections. We first assessed the efficacy of two anthelmintic treatments, ivermectin and pyrantel pamoate, in wild-caught M. natalensis, finding that both treatments significantly reduced gastrointestinal nematodes, with pyrantel pamoate being more effective than ivermectin. Additionally, we examined how helminth reduction influenced microparasite prevalence. Our results show that pyrantel pamoate treatment was associated with a decrease in Morogoro virus seropositivity over time, while anthelmintic treatment had no significant effect on Bartonella infection probability.

ecology↗

bioRxiv2024

Antibodies against medically relevant arthropod-borne viruses in the ubiquitous African rodent Mastomy natalensis

Over the past decades, the number of arthropod-borne virus (arbovirus) outbreaks has increased worldwide. Knowledge regarding the sylvatic cycle (i.e., non-human hosts/environment) of arboviruses is limited, particularly in Africa, and the main hosts for virus maintenance are unknown. Previous studies have shown the presence of antibodies against certain arboviruses (i.e., chikungunya-, dengue- and zika virus) in African non-human primates and bats. We hypothesize that small mammals, specifically rodents, may function as amplifying hosts in anthropogenic environments. The detection of RNA of most arboviruses is complicated by the viruss short viremic period within their hosts. An alternative to determine arbovirus hosts is by detecting antibodies, which can persist several months. We developed a high-throughput multiplex immunoassay to detect antibodies against 15 medically relevant arboviruses. We used this assay to assess almost 1,300 blood samples of the multimammate mouse, Mastomys natalensis from Tanzania. In 24% of the samples, we detected antibodies against at least one of the tested arboviruses, with high seroprevalences of antibodies reacting against dengue virus serotype one (7.6%) and two (8.4%) and chikungunya virus (6%). Seroprevalence was higher in females and increased with age, which could be explained by inherent immunity and behavioral differences between sexes and the increased chance of exposure to an arbovirus with age. We evaluated whether antibodies against multiple arboviruses co-occur more often than randomly and found that this may be true for some members of the Flaviviridae and Togaviridae. In conclusion, the development of an assay against a wide diversity of medically relevant arboviruses enabled the analysis of a large sample collection of one of the most abundant African small mammals. Our findings suggest a role in the transmission of multiple arboviruses by this ubiquitous rodent and provide a solid foundation for future molecular screening to elucidate the role in the arbovirus transmission cycle. Author summaryOne of the main causes of zoonotic related human morbidity and mortality is the transmission of arthropod-borne viruses such as dengue virus, Yellow Fever virus, and chikungunya virus. These viruses cannot only infect humans but also livestock, pets, and wildlife, though our understanding of their non-human hosts remains limited. Rodents are thought to be an interesting host for these viruses because they can be abundant, often live near humans and some are already known to be viral hosts. However, research has focused on non-human primates, neglecting other potential hosts. To address this gap, we have developed a high-throughput antibody test to screen rodent blood against 15 different arboviruses. Our findings reveal that a proportion of Mastomys natalensis, a common African rodent species, carry antibodies that (cross-)react against these viruses. We hypothesize that immunologically naive juveniles may drive transmission, particularly during population outbreaks. These outbreaks coincide with environmental conditions that are favorable for mosquitoes, the vectors of these viruses. Thus, increasing the risk of spillover to humans, livestock, and wildlife. Understanding the role of rodents in arbovirus transmission dynamics is crucial for mitigating zoonotic disease risks.

immunology↗

bioRxiv2022

Host related factors determine co-occurrence patterns between pathogenic bacteria, protozoa, and helminths in populations of the multimammate mouse, Mastomys natalensis

Advances in experimental and theoretical work increasingly suggest that parasite interactions within a single host can affect the spread and severity of wildlife diseases. Yet empirical data to support predicted co-infection patterns are limited due to the practical challenges of gathering convincing data from animal populations and the stochastic nature of parasite transmission. Here, we investigated co-infection patterns between micro- (bacteria and protozoa) and macroparasites (gastrointestinal helminths) in natural populations of the multimammate mouse (Mastomys natalensis). Fieldwork was performed in Morogoro (Tanzania), where we trapped 211 individual M. natalensis and tested their behavior using a modified open-field arena. All animals were checked on the presence of helminths in their gastrointestinal tract, three bacteria (Anaplasma, Bartonella, and Borrelia) and two protozoan genera (Piroplasma and Hepatozoon). Besides the presence of eight different helminth genera (reported earlier), we found that 21% of M. natalensis were positive for Anaplasma, 13% for Bartonella, and 2% for Hepatozoon species. Hierarchical modelling of species communities was used to investigate the effect of the different host-related factors on these parasites infection probability and community structure. Our results show that the infection probability of Anaplasma and Bartonella was higher in adults than juveniles. We also observed that females and less explorative individuals had a higher infection probability with Bartonella. We found limited support for within-host interactions between micro-and macroparasites, as only animals infected with Bartonella were significantly more likely to be infected with Protospirura, Trichuris, and Trichostrongylidae helminths.

ecology↗

bioRxiv2021

SARS-CoV-2 surveillance in Norway rats (Rattus norvergicus) from Antwerp sewer system, Belgium

BackgroundSARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans. AimWe tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples. MethodsBetween November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT). ResultsThe serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA. ConclusionThis is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.

ecology↗

bioRxiv2019

Feeding behavior and activity of Phlebotomus pedifer and potential reservoir hosts of Leishmania aethiopica in southwestern Ethiopia.

BackgroundCutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and established the role of livestock in CL transmission. MethodsBlood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from goats and bovines were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches (HLC) and CDC light traps to determine at which time and where P. pedifer is mostly active. Principal findingsA total of 180 sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source (59.4%, p < 0.001) in all habitats, even in caves, where hyraxes are abundant. Only 10.6% of the sand flies fed on hyraxes based on the blood meal analysis, but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes over humans (p = 0.009) when hosts are equally accessible. Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial amount of sand flies was active in the early evening, which increased over time reaching its maximum around midnight. ConclusionWe indicate that Leishmania transmission in southwestern Ethiopia is, in contrast to earlier suggestions, likely mainly anthroponotic and that livestock does not play a role in transmission. Combined indoor and outdoor vector control measures at night are required for efficient vector control. Author summaryCutaneous leishmaniasis is a major public health problem in Ethiopia. It is caused by Leishmania aethiopica protozoa that are transmitted when female sand flies take a blood meal. Hyraxes are assigned as the reservoirs of the infection, because many were found infected with Leishmania. There is very limited knowledge about the behavior of sand flies and other potential hosts of the infection. However, this information is a prerequisite for disease control, which is currently hampered. In this study, we found that humans are likely the main source of the infection and that the role of hyraxes in disease transmission needs further investigation to decide whether they should be included in control programs. Livestock appears not play a role in transmission, even though sand flies like to feed on them. We also show that sand flies are active indoors and outdoors, but have a preference for feeding inside human dwellings and that they are mostly active around midnight. Overall, we conclude that disease prevention and control should emphasize on human protection by applying vector control indoors, at night.

ecology↗

bioRxiv2017

Comparing arenavirus infection patterns in experimentally and naturally infected rodent hosts

Infectious diseases of wildlife are typically studied using data on antibody and pathogen presence/level. In order to interpret these data, it is necessary to know the course of antibodies and pathogen presence/levels after infection. Such data are typically collected using experimental infection studies in which host individuals are inoculated in the laboratory and sampled over an extended period, but because laboratory conditions are controlled and much less variable than natural conditions, the immune response and pathogen dynamics may differ. Here, we compared Morogoro arenavirus infection patterns between naturally and experimentally infected multimammate mice (Mastomys natalensis). Longitudinal samples were collected during three months of bi-weekly trapping in Morogoro, Tanzania, and antibody titer and viral RNA presence were determined to assess whether the natural temporal patterns are similar to those previously observed in the laboratory. A good match with laboratory data was found for 52% of naturally infected individuals, while most of the mismatches can be explained by the presence of chronically infected individuals (35%), maternal antibodies (10%) and an antibody detection limit (25%). These results suggest that while laboratory data are useful for interpreting field samples, there can still be differences due to conditions that were not tested in the laboratory.\n\nImportant noticeThis is a pre-print version of the manuscript, made available through bioRxiv.org. Note that this manuscript has not yet been peer-reviewed, and has been submitted to a peer-reviewed journal.

immunology↗