Brian Fredensborg

• PhD
• Professor (Associate) at University of Copenhagen

Parasite-induced modification of host behavior increasing transmission to a next host is a common phenomenon. However, field-based studies are rare, and the role of environmental factors in eliciting host behavioral modification is often not considered. We examined the effects of temperature, relative humidity (RH), time of day, date, and an irradi...

The global biodiversity crisis emphasizes our need to understand how different stressors (climatic, chemical, parasitic, etc.) interact and affect biological communities. We provide a comprehensive meta-analysis investigating joint effects of chemical and parasitic stressors for 1064 chemical-parasitic combinations using the Multiplicative model on...

The neglected tropical disease trichuriasis is caused by the whipworm Trichuris trichiura,a soil-transmitted helminth that has infected humans for millennia. Today, T. trichiura infects as many as 500 million people, predominantly in communities with poor sanitary infrastructure enabling sustained faecal-oral transmission. Using whole-genome sequen...

The neglected tropical disease trichuriasis is caused by the whipworm Trichuris trichiura, a soil-transmitted helminth that has infected humans for millennia. Today, T. trichiura infects as many as 500 million people, predominantly in communities with poor sanitary infrastructure enabling sustained faecal-oral transmission. Using whole-genome seque...

The probiotic medicinal product TSO (Trichuris suis ova) is administered to patients with active ulcerative colitis in an ongoing clinical phase IIb trial where the typical co-medications are steroids (prednisolone or budesonide) and antibiotics (e.g., phenoxymethylpenicillin). The present pre-clinical study evaluates the effects of these co-medica...

Host-parasite interactions may be modulated by host- or parasite-associated microbes, but the role of these are often overlooked. Particularly for parasites with intestinal stages (either larval or adult), the host gut microbiome may play a key role for parasite establishment; moreover, the microbiome may change in response to invading parasites. H...

It is widely accepted that sensitivity towards pesticides varies significantly between species. Much less is known about the potential differences in pesticide sensitivity and its biological mechanism throughout the lifecycle of a single species. In the present study we used three life-stages (larvae, pupae and adult) of the holometabolous insect T...

Environmental toxicants are pervasive in nature, but sub-lethal effects on non-target organisms and their parasites are often overlooked. Particularly, studies on terrestrial hosts and their parasites exposed to agricultural toxicants are lacking. Here, we studied the effect of sequence and timing of sub-lethal exposures of the pyrethroid insectici...

The negative effects of pesticides on beneficial terrestrial invertebrates have received much attention, and in this context quantification of the activity of metabolic enzymes provides an important tool. Unfortunately, current methodologies are limited in their use. In this study, the grain beetle, Tenebrio molitor was used to illustrate why in vi...

Biological control agents based on entomopathogenic fungi traditionally contain a single strain that is efficient under certain biotic and abiotic conditions. Since particularly abiotic conditions vary, biological control efficiency may become more resilient at extreme temperatures if two or more fungal strains are combined based on their adaptatio...

The present note reports the first authenticated record of Neoneurinae wasps (Hymenoptera: Braconidae) parasitizing ants (Hymenoptera: Formicidae) in Denmark. This is based on a first instar larva of a probable species of Elasmosoma (Ruthe) developing in the body cavity of a worker ant, Formica polyctena (Förster 1850), in the Northern part of Bids...

Mounting evidence suggests that the transmission of certain parasites is facilitated by increasing temperatures, causing their host population to decline. However, no study has yet addressed how temperature and parasitism may combine to shape the functional structure of a whole host community in the face of global warming. Here, we apply an outdoor...

High-resolution insight into parasitic infections and diet of past populations in Northern Europe and the Middle East (500 BC- 1700 AD) was obtained by pre-concentration of parasite eggs from ancient latrines and deposits followed by shotgun sequencing of DNA. Complementary profiling of parasite, vertebrate and plant DNA proved highly informative i...

Description of sampling locations. (DOCX)

Sequencing libraries information. (XLSX)

Sequencing reads assigned to helminths. (XLSX)

Sequencing read assignment using plastid database. (XLSX)

Sequencing reads assigned to vertebrates. (XLSX)

Sample level information. (XLSX)

Mitochondrial genome coverage and damage. (XLSX)

BACKGROUND Combining low doses of chemical insecticides with entomopathogens constitutes a sustainable pest control method, but significance of timing and sequence of exposures needs clarification. We studied lethal effects of combinations of the entomopathogenic fungus Beauveria bassiana (KVL03‐122) and the pyrethroid alpha‐cypermethrin on the bee...

Dicrocoelium dendriticum, the lancet liver fluke, is one of the best examples of parasite-induced host behaviour manipulation. The parasite elicits a behaviour in the second intermediate ant host which is alien to an uninfected ant. A D. dendriticum infected ant will lock its mandibles to a piece of vegetation (tetania) and remain there for the tim...

Parasite effects on host fitness and immunology are often intensity-dependent. Unfortunately, only few experimental studies on insect-parasite interactions attempt to control the level of infection, which may contribute substantial variation to the fitness or immunological parameters of interest. The tapeworm Hymenolepis diminuta—flour beetle Teneb...

Brian Lund Fredensborg and I, explained parasitic manipulation of host behaviour in a magazine used as inspiration for the teaching of biology in schools in Denmark. We covered some of the most amazing examples from nature, and with emphasis on the parasites that turn ants into zombies in Denmark: Dicrocoelium dendriticum and Pandora formicae. A fe...

Chagas disease caused by Trypanosoma cruzi is a burden to millions of people in South and Central America. A sylvatic life cycle of the parasite exists in the Southern United States, but recent studies indicate an active peri-domestic life cycle of T. cruzi in Texas. The USA-Mexico border region in Texas displays areas of high poverty and sub-stand...

In the western world edible insects have gained increased recognition for their taste, nutritional value, and potential for commercial-scale production of foods for human consumption and animal feed. The presence of food-borne parasites in insects is therefore a concern due to the potential hazards it may cause consumers. In this study we developed...

The lancet fluke, Dicrocoelium dendriticum is perhaps the best known example of parasite manipulation of host behavior, which is manifested by a radically changed behavior which leaves infected ants attached to vegetation at times when transmission to an herbivore host is optimal. Despite the publicity surrounding this parasite curiously little is...

Host behavioural modification by parasites is a common and well-documented phenomenon. However, knowledge on the complexity and specificity of the underlying mechanisms is limited, and host specificity among manipulating parasites has rarely been experimentally verified. We tested the hypothesis that the ability to infect and manipulate host behavi...

Invertebrate models provide several important advantages over their vertebrate counterparts including fewer legislative stipulations and faster, more cost-effective experimental procedures. Furthermore, various similarities between insect and mammalian systems have been highlighted. To obtain maximum use of invertebrate models in pharmacology, thei...

The majority of wild foods consumed by humans are sourced from intensively managed or semi-farmed populations. Management practices inevitably affect wildlife density and habitat characteristics, which are key elements in the transmission of parasites. We consider the risk of transmission of foodborne parasites to humans from wildlife maintained un...

Echinococcus multilocularis (EM) is a pathogenic and potentially fatal cestode causing human alveolar echinococcosis (AE). A meta-analysis was conducted using a generalized estimation equation approach (GEE) to assess the effect of taxonomic, environmental and diagnostic variables on EM prevalence in different hosts. Red foxes (Vulpes vulpes) had s...

Natural anti-parasitic compounds in plants such as condensed tannins (CT) have anthelmintic properties against a range of gastrointestinal nematodes, but for other helminths such effects are unexplored. The aim of this study was to assess the effects of CT from three different plant extracts in a model system employing the rat tapeworm, Hymenolepis...

Abstract Ancient parasite eggs were recovered from environmental samples collected at a Viking-age settlement in Viborg, Denmark, dated 1018-1030 A.D. Morphological examination identified Ascaris sp., Trichuris sp. and Fasciola sp. eggs, but size and shape did not allow species identification. By carefully selecting genetic markers, PCR amplificati...

A trade-off between resource-specialization and the breadth of the ecological niche is one of the most fundamental biological characteristics. A true generalist (Jack-of-all-trades) displays a broad ecological niche with little resource specialization while the opposite is true for a resource-specialist that has a restricted ecological niche that i...

Abstract In this study, we investigated oysters, Crassostrea virginica from Laguna Madre in South Texas where a 45-yr old study recorded metacercarial infections of the echinostomatid trematode, Acanthoparyphium spinulosum, which relative in Asia A. tyosenense has been associated with human infections via the ingestion of raw mollusks. In an effort...

The transmission stages of parasites are key determinants of parasite fitness, but they also incur huge mortality. Yet the selective forces shaping the sizes of transmission stages remain poorly understood. We ran a comparative analysis of interspecific variation in the size of transmission stages among 404 species of parasitic trematodes. There ar...

Abstract : Some parasites modify the behavior of intermediate hosts to increase the probability of transmission to the next host in their life cycle. In habitats where this is common, parasites play an important role in predator-prey links and food web dynamics. In this study we used laboratory observations to investigate the behavior of longnose k...

Ecological theory predicts that specialization increases the exploitation of a suitable niche at the expense of the number of suitable niches. The degree of host specificity of Euhaplorchis sp., a specialist parasite encysting on the brain and manipulating its fish host behavior, was tested based on the phylogeny of five fish species; the Sheepshea...

Background/Question/Methods The Laguna Madre, South Texas/ North-Eastern Mexico is one of just five hypersaline estuaries in the World and the only one of its kind on the North American continent. The estuary harbors extensive seagrass beds which serve as habitat for a high diversity of animal species. Several anthropogenic chemicals and in parti...

Background/Question/Methods The Red Queen Hypothesis is one of the most important contributions to ecological theory explaining the evolution and maintenance of sex. The hypothesis predicts that recombination of genetic material following sexual reproduction allows organisms to evolve resistance to parasites, disease, predators and adverse enviro...

Background/Question/Methods Chagas disease is an important parasitic disease caused by the flagellate protozoan Trypanosoma cruzi, bringing great distress to the public health field in the Americas. T. cruzi is known for utilizing Triatominae insects (kissing bugs) as vectors in areas with a tropical/subtropical humid habitat. In this study the p...

Larval tapeworms (Polypocephalus sp.) reside within the central nervous system of decapod crustaceans. Living within the nervous system would seem to create an excellent opportunity for the parasites to manipulate the behavior of their hosts, so we tested the hypothesis that behavior of white shrimp ( Litopenaeus setiferus ) would be correlated wit...

This data set presents food webs for three North American Pacific coast estuaries and a ‘‘Metaweb’’ composed of the species/stages compiled from all three estuaries. The webs have four noteworthy attributes: (1) parasites (infectious agents), (2) body-size information, (3) biomass information, and (4) ontogenetic stages of many animals with complex...

Background/Question/Methods Parasites are widespread and ubiquitous organisms, contributing a substantial amount of biomass to both aquatic and terrestrial ecosystems. Since biomass and energetics are related, we conjecture that parasites would have a considerable impact on the flow of energy through a system. In order to study how parasitism influ...

Little is known about the patterns of variation in parasitism in marine hosts. Trematodes, the dominant parasites in intertidal systems, are transmitted from their first intermediate hosts (snails) to a range of second intermediate hosts, including crustaceans. Using published studies of trematode infections in crustacean hosts, we investigated gen...

Despite the important roles played by parasites in local population dynamics and community structure of marine ecosystems, there is a lack of information on the geographical variation in infection levels displayed by particular host–parasite species combinations. This study examines geographical variation in infection levels by the metacercarial st...

Parasites, in particular trematodes, are unseen but ubiquitous components of marine intertidal ecosystems. Although parasites are known to affect population dynamics and food web structure, their potential function as an unrecognized path of energy flow in these ecosystems is yet to be quantified. We use published data on rates at which trematodes...

Parasites can have strong impacts but are thought to contribute little biomass to ecosystems. We quantified the biomass of free-living and parasitic species in three estuaries on the Pacific coast of California and Baja California. Here we show that parasites have substantial biomass in these ecosystems. We found that parasite biomass exceeded that...

The cercariae and sporocysts (or rediae) of four trematode species are described from the intertidal snail Zeacumantus subcarinatus: a distome xiphidiocercaria assigned to the genus Renicola (family Renicolidae); a monostome xiphidiocercaria belonging either to the genus Microphallus or Mega-lophallus (family Microphallidae); a magnacercous cercari...

Variation in life‐history strategies among conspecific populations indicates the action of local selective pressures; recently, parasitism has been suggested as one of these local forces. Effects of trematode infections on reproductive effort, juvenile growth, size at maturity and susceptibility were investigated among different natural populations...

Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a reduction in size, caused by crowding, virtually noth...

The shell morphology of mud snails, Zeacumantussubcarinatus, both uninfected and infected by trematodes, was compared to determine if different trematode species induce different degrees of alteration in host shell shape. Snails harbouring either the echinostomatid Acanthoparyphium sp., or a double infection by the microphallid Maritremanovaezealan...

Shorebird abundance and spatial distribution of larval trematodes in the New Zealand mudsnail, Zeacumantus subcarinatus, were investigated in soft-sediment intertidal bays within Otago Harbour, South Island, New Zealand. In a small-scale study, recruitment of trematodes to caged sentinel snails and the prevalence of infection in free-living snails...

Ecological studies have demonstrated that parasites are capable of influencing various aspects of host life history and can play an important role in the structure of animal populations. We investigated the influence of infection by castrating trematodes on the reproduction, survival and population density of the intertidal snail Zeacumantus subcar...

In this study, the effect of the composition of culture medium on excystation, growth, survival and egg production was investigated for the recently discovered microphallid trematode Maritrema novaezealandensis. Metacercariae from the two second intermediate crab hosts, Macrophthalmus hirtipes and Halicarcinus whitei, were incubated in either: (1)...

The potential impact of parasitism on pairing patterns of the amphipod Paracalliope fluviatilis was investigated with regard to the infection status of both males and females. Two helminth parasites commonly use this crustacean species as second intermediate host. One of them, Coitocaecum parvum, is a progenetic trematode with an egg-producing meta...

The impact of parasitism on population dynamics and community structure of marine animals is an area of growing interest in marine ecology. The effect of a microphallid trematode, Maritrema novaezelandensis on the survival of its amphipod host, Paracalliope novizealandiae, was investigated by a laboratory study combined with data from field collect...

Maritrema novaezealandensis n. sp. is described from Otago Harbor, South Island, New Zealand, on the basis of adult specimens collected from the Red-billed gull, Larus novaehollandiae scopulinus, and excysted metacercariae obtained from crabs. It belongs to the "eroliae group" and differs from other related species mainly in the shape, size, and pa...

Eight species of gastrointestinal helminths were obtained from the red-billed gull (Larus novaehollandiae scopulinus Forster, 1844) from Otago Peninsula, of which six were new host records. One of these, Maritrema novaezelandensis (Trematoda), was a species new to science which is being described elsewhere; the other five were Curtuteria australis...

The whelk Cominella glandiformis is an important predator-scavenger of New Zealand intertidal ecosystems; a few whelks can quickly eat all the soft tissues of recently dead crabs. In this study, we demonstrate that whelks can also ingest and act as paratenic hosts for at least 4 helminth species that use crabs as intermediate hosts: metacercariae o...

Previously undescribed third-stage larvae of two species of Spirurida were found in the haemocoel of the stalk-eyed mud crab Macrophthalmus hirtipes (Heller) (Ocypodidae) in New Zealand. Examinations by light and scanning electron microscopy showed that the larger larvae (about 7 mm long) belonged to a species of Ascarophis van Beneden, 1871 (Cysti...