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Tolf, Conny
Publications (10 of 37) Show all publications
Williams, R. A. J., Tolf, C. & Waldenström, J. (2018). Molecular identification of papillomavirus in ducks. Scientific Reports, 8, Article ID 9096.
Open this publication in new window or tab >>Molecular identification of papillomavirus in ducks
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 9096Article in journal (Refereed) Published
Abstract [en]

Papillomaviruses infect many vertebrates, including birds. Persistent infections by some strains can cause malignant proliferation of cells (i.e. cancer), though more typically infections cause benign tumours, or may be completely subclinical. Sometimes extensive, persistent tumours are recorded-notably in chaffinches and humans. In 2016, a novel papillomavirus genotype was characterized from a duck faecal microbiome, in Bhopal, India; the sixth papillomavirus genotype from birds. Prompted by this finding, we screened 160 cloacal swabs and 968 faecal samples collected from 299 ducks sampled at Ottenby Bird Observatory, Sweden in 2015, using a newly designed real-time PCR. Twenty one samples (1.9%) from six individuals (2%) were positive. Eighteen sequences were identical to the published genotype, duck papillomavirus 1. One additional novel genotype was recovered from three samples. Both genotypes were recovered from a wild strain domestic mallard that was infected for more than 60 days with each genotype. All positive individuals were adult (P = 0.004). Significantly more positive samples were detected from swabs than faecal samples (P < 0.0001). Sample type data suggests transmission may be via direct contact, and only infrequently, via the oral-faecal route. Infection in only adult birds supports the hypothesis that this virus is sexually transmitted, though more work is required to verify this.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Ecology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-76872 (URN)10.1038/s41598-018-27373-6 (DOI)000435338100011 ()29904122 (PubMedID)2-s2.0-85048835779 (Scopus ID)
Available from: 2018-07-17 Created: 2018-07-17 Last updated: 2019-08-29Bibliographically approved
Andersson, M. O., Tolf, C., Tamba, P., Stefanache, M., Radbea, G., Frangoulidis, D., . . . Chitimia-Dobler, L. (2018). Molecular survey of neglected bacterial pathogens reveals an abundant diversity of species and genotypes in ticks collected from animal hosts across Romania. Parasites & Vectors, 11, Article ID 144.
Open this publication in new window or tab >>Molecular survey of neglected bacterial pathogens reveals an abundant diversity of species and genotypes in ticks collected from animal hosts across Romania
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2018 (English)In: Parasites & Vectors, ISSN 1756-3305, E-ISSN 1756-3305, Vol. 11, article id 144Article in journal (Refereed) Published
Abstract [en]

Background: Ticks are transmitting a wide range of bacterial pathogens that cause substantial morbidity and mortality in domestic animals. The full pathogen burden transmitted by tick vectors is incompletely studied in many geographical areas, and extensive studies are required to fully understand the diversity and distribution of pathogens transmitted by ticks. Results: We sampled 824 ticks of 11 species collected in 19 counties in Romania. Ticks were collected mainly from dogs, but also from other domestic and wild animals, and were subjected to molecular screening for pathogens. Rickettsia spp. was the most commonly detected pathogen, occurring in 10.6% (87/824) of ticks. Several species were detected: Rickettsia helvetica, R. raoultii, R. massiliae, R. monacensis, R. slovaca and R. aeschlimannii. A single occurrence of the zoonotic bacterium Bartonella vinsonii berkhoffii was detected in a tick collected from a dog. Anaplasma phagocytophilum occurred in four samples, and sequences similar to Anaplasma marginale/ovis were abundant in ticks from ruminants. In addition, molecular screening showed that ticks from dogs were carrying an Ehrlichia species identical to the HF strain as well as the enigmatic zoonotic pathogen "Candidatus Neoehrlichia mikurensis". An organism similar to E. chaffeensis or E. muris was detected in an Ixodes ricinus collected from a fox. Conclusions: We describe an abundant diversity of bacterial tick-borne pathogens in ticks collected from animal hosts in Romania, both on the level of species and genotypes/strains within these species. Several findings were novel for Romania, including Bartonella vinsonii subsp. berkhoffii that causes bacteremia and endocarditis in dogs. "Candidatus Neoehrlichia mikurensis" was detected in a tick collected from a dog. Previously, a single case of infection in a dog was diagnosed in Germany. The results warrant further studies on the consequences of tick-borne pathogens in domestic animals in Romania.

Place, publisher, year, edition, pages
BioMed Central, 2018
Keywords
Ticks, Neglected bacterial pathogens, Animal hosts, Romania
National Category
Microbiology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-72690 (URN)10.1186/s13071-018-2756-1 (DOI)000428286800001 ()29554947 (PubMedID)2-s2.0-85044202572 (Scopus ID)
Available from: 2018-04-13 Created: 2018-04-13 Last updated: 2019-08-29Bibliographically approved
Lawson, B., Robinson, R. A., Fernandez, J.-R. R., John, S. K., Benitez, L., Tolf, C., . . . Williams, R. A. J. (2018). Spatio-temporal dynamics and aetiology of proliferative leg skin lesions in wild British finches. Scientific Reports, 8, Article ID 14670.
Open this publication in new window or tab >>Spatio-temporal dynamics and aetiology of proliferative leg skin lesions in wild British finches
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 14670Article in journal (Refereed) Published
Abstract [en]

Proliferative leg skin lesions have been described in wild finches in Europe although there have been no large-scale studies of their aetiology or epizootiology to date. Firstly, disease surveillance, utilising public reporting of observations of live wild finches was conducted in Great Britain (GB) and showed proliferative leg skin lesions in chaffinches (Fringilla coelebs) to be widespread. Seasonal variation was observed, with a peak during the winter months. Secondly, pathological investigations were performed on a sample of 39 chaffinches, four bullfinches (Pyrrhula pyrrhula), one greenfinch (Chloris chloris) and one goldfinch (Carduelis carduelis) with proliferative leg skin lesions and detected Cnemidocoptes sp. mites in 91% (41/45) of affected finches and from all species examined. Fringilla coelebs papillomavirus (FcPV1) PCR was positive in 74% (23/31) of birds tested: a 394 base pair sequence was derived from 20 of these birds, from all examined species, with 100% identity to reference genomes. Both mites and FcPV1 DNA were detected in 71% (20/28) of birds tested for both pathogens. Histopathological examination of lesions did not discriminate the relative importance of mite or FcPV1 infection as their cause. Development of techniques to localise FcPV1 within lesions is required to elucidate the pathological significance of FcPV1 DNA detection.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Zoology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-78461 (URN)10.1038/s41598-018-32255-y (DOI)000446854300001 ()30305642 (PubMedID)2-s2.0-85054775152 (Scopus ID)
Available from: 2018-10-24 Created: 2018-10-24 Last updated: 2019-08-29Bibliographically approved
Wille, M., Latorre-Margalef, N., Tolf, C., Halpin, R., Wentworth, D., Fouchier, R. A. M., . . . Waldenström, J. (2018). Where do all the subtypes go?: Temporal dynamics of H8-H12 influenza A viruses in waterfowl. Virus Evolution, 4(2), Article ID vey025.
Open this publication in new window or tab >>Where do all the subtypes go?: Temporal dynamics of H8-H12 influenza A viruses in waterfowl
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2018 (English)In: Virus Evolution, E-ISSN 2057-1577, Vol. 4, no 2, article id vey025Article in journal (Refereed) Published
Abstract [en]

Influenza A virus (IAV) is ubiquitous in waterfowl. In the northern hemisphere IAV prevalence is highest during the autumn and coincides with a peak in viral subtype diversity. Although haemagglutinin subtypes H1-H12 are associated with waterfowl hosts, subtypes H8-H12 are detected very infrequently. To better understand the role of waterfowl in the maintenance of these rare subtypes, we sequenced H8-H12 viruses isolated from Mallards (Anas platyrhynchos) from 2002 to 2009. These rare viruses exhibited varying ecological and phylodynamic features. The Eurasian clades of H8 and H12 phylogenies were dominated by waterfowl sequences; mostly viruses sequenced in this study. H11, once believed to be a subtype that infected charadriiformes (shorebirds), exhibited patterns more typical of common virus subtypes. Finally, subtypes H9 and H10, which have maintained lineages in poultry, showed markedly different patterns: H10 was associated with all possible NA subtypes and this drove HA lineage diversity within years. Rare viruses belonging to subtypes H8-H12 were highly reassorted, indicating that these rare subtypes are part of the broader IAV pool. Our results suggest that waterfowl play a role in the maintenance of these rare subtypes, but we recommend additional sampling of non-traditional hosts to better understand the reservoirs of these rare viruses.

Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
disease ecology, evolutionary genetics, influenza A, mallards, pathogen dynamics, subtype diversity
National Category
Microbiology
Research subject
Biomedical Sciences, Virology; Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-80290 (URN)10.1093/ve/vey025 (DOI)000456426800007 ()30151242 (PubMedID)
Available from: 2019-02-08 Created: 2019-02-08 Last updated: 2019-02-08Bibliographically approved
Andersson, M. O., Tolf, C., Tamba, P., Stefanache, M., Radbea, G., Rubel, F., . . . Chitimia-Dobler, L. (2017). Babesia, Theileria, and Hepatozoon species in ticks infesting animal hosts in Romania. Parasitology Research, 116(8), 2291-2297
Open this publication in new window or tab >>Babesia, Theileria, and Hepatozoon species in ticks infesting animal hosts in Romania
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2017 (English)In: Parasitology Research, ISSN 0932-0113, E-ISSN 1432-1955, Vol. 116, no 8, p. 2291-2297Article in journal (Refereed) Published
Abstract [en]

Babesia spp., Theileria spp., and Hepatozoon spp. are tick-transmitted apicomplexan parasites that cause several important diseases in animals. To increase current knowledge about the diversity of tick-transmitted pathogens in Romania, we investigated the occurrence of Babesia spp., Theileria spp., and Hepatozoon spp. in a wide range of tick species infesting animal hosts. We collected 852 ticks from 10 different animal species from 20 counties in Romania. The assessment was based on detection of parasite DNA by PCR. Five different apicomplexan parasite species were detected; among them three different species of Babesia: B. canis, B. microti, and B. ovis. Hepatozoon canis was the most frequently detected parasite, found predominately in Ixodes ricinus ticks collected from domestic dogs. It was also detected in I. ricinus collected from goat, fox, and cat. Furthermore, H. canis was found in Haemaphysalis punctata and Haemaphysalis concinna ticks. In addition, Theileria buffeli was detected in Rhipicephalus bursa ticks collected from cattle.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Ticks, Babesia, Theileria, Hepatozoon, Romania
National Category
Microbiology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-67500 (URN)10.1007/s00436-017-5537-4 (DOI)000406423300026 ()2-s2.0-85021826833 (Scopus ID)
Available from: 2017-08-29 Created: 2017-08-29 Last updated: 2019-08-29Bibliographically approved
Andersson, M. O., Tolf, C., Tamba, P., Stefanache, M., Waldenström, J., Dobler, G. & Chitimia-Dobler, L. (2017). Canine tick-borne diseases in pet dogs from Romania. Parasites & Vectors, 10, Article ID 2092.
Open this publication in new window or tab >>Canine tick-borne diseases in pet dogs from Romania
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2017 (English)In: Parasites & Vectors, ISSN 1756-3305, E-ISSN 1756-3305, Vol. 10, article id 2092Article in journal (Refereed) Published
Abstract [en]

Background: Tick-borne diseases are of substantial concern worldwide for animals as well as humans. Dogs have been a human companion for millennia, and their significant impact on human life renders disease in dogs to be of great concern. Tick-borne diseases in dogs represent a substantial diagnostic challenge for veterinarians in that clinical signs are often diffuse and overlapping. In addition, co-infections with two or more pathogens enhance this problem further. Molecular methods are useful to disentangle co-infections and to accurately describe prevalence and geographical distribution of tick-borne diseases. At this point, this information is lacking in many areas worldwide. Romania is one such area, where prevalence and distribution of several important pathogens need to be further investigated. To address this, we screened blood samples from 96 sick dogs with molecular methods for eight different pathogens including Babesia spp., Theileria spp., Hepatozoon spp., Anaplasma spp., Ehrlichia spp., "Candidatus Neoehrlichia mikurensis", Mycoplasma spp., and Borrelia spp. Results: As many as 45% (43/ 96) of the dogs in the study were infected with protozoan parasites. Babesia canis was the most frequent of these (28 infected dogs), whereas Hepatozoon canis was detected in 15% (14/ 96) and Babesia gibsoni was found in a single sample. Bacterial infection with Mycoplasma spp. occurred in 18% (17/ 96) of the sampled dogs. Obtained bacterial sequences revealed the occurrence of two species: Mycoplasma canis and "Candidatus Mycoplasma haematoparvum". In several cases co-infection with protozoan parasites and Mycoplasma sp. were detected. All dogs were negative for Anaplasma spp., Ehrlichia spp., "Ca. Neoehrlichia mikurensis", and for Borrelia spp. Conclusions: The results from the present study reinforce the notion that Babesia canis is an important pathogen in the Romanian dog population. However, more surprisingly, another protozoan species, H. canis, seems to be infecting dogs to a larger extent than previously recognized in Romania. Well-known tick-borne bacterial disease agents such as Anaplasma spp. and Borrelia spp. were not detected. In contrast, less wellstudied bacteria such as hemotropic Mycoplasma spp. were detected frequently. Moreover, co-infection might aggravate disease and complicate diagnosis and should be further studied in dogs.

Place, publisher, year, edition, pages
BioMed Central, 2017
Keywords
Dogs, Canis familiaris, Vector-borne diseases, Tick-borne diseases, Romania
National Category
Biological Sciences
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-64194 (URN)10.1186/s13071-017-2092-x (DOI)000397764500003 ()28335825 (PubMedID)2-s2.0-85016121197 (Scopus ID)
Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2019-08-29Bibliographically approved
Andersson, M. O., Vichova, B., Tolf, C., Krzyzanowska, S., Waldenström, J. & Karlsson, M. E. (2017). Co-infection with Babesia divergens and Anaplasma phagocytophilum in cattle (Bos taurus), Sweden. Ticks and Tick-borne Diseases, 8(6), 933-935
Open this publication in new window or tab >>Co-infection with Babesia divergens and Anaplasma phagocytophilum in cattle (Bos taurus), Sweden
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2017 (English)In: Ticks and Tick-borne Diseases, ISSN 1877-959X, E-ISSN 1877-9603, Vol. 8, no 6, p. 933-935Article in journal (Refereed) Published
Abstract [en]

Babesiosis is a severe disease in cattle worldwide. In Europe, the main causative agent of bovine babesiosis is Babesia divergens. In some areas, this species is reported to have declined or even disappeared, and its etiological role overtaken by other piroplasmid species. Moreover, co-infection with other tick-transmitted pathogens can be expected to complicate diagnosis in cattle. Hence, molecular identification of the causative agent of babesiosis should be a priority. Therefore, samples from 71 domestic cattle, 39 with clinical signs of babesiosis and 32 without, from southern Sweden were screened for Babesia spp. and Anaplasma spp. using molecular methods Babesia divergens was detected in 38 of the samples, and Anaplasma phagocytophilum in 17. Co-infections with both pathogens were frequent, occurring in 18% of the animals with a B. divergens infection. The possibility of co-infection should be considered in diagnosis and treatment of bovine babesiosis.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Co-infection, Zoonotic disease, Tick-borne disease, Sweden
National Category
Microbiology Ecology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-68560 (URN)10.1016/j.ttbdis.2017.08.005 (DOI)000412378600018 ()28869191 (PubMedID)2-s2.0-85028363647 (Scopus ID)
Available from: 2017-11-01 Created: 2017-11-01 Last updated: 2019-08-29Bibliographically approved
Wille, M., Latorre-Margalef, N., Tolf, C., Stallknecht, D. E. & Waldenström, J. (2017). No evidence for homosubtypic immunity of influenza H3 in Mallards following vaccination in a natural experimental system. Molecular Ecology, 26(5), 1420-1431
Open this publication in new window or tab >>No evidence for homosubtypic immunity of influenza H3 in Mallards following vaccination in a natural experimental system
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2017 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 26, no 5, p. 1420-1431Article in journal (Refereed) Published
Abstract [en]

The Mallard (Anas platyrhynchos) is an important reservoir species for influenza A viruses (IAV), and in this host, prevalence and virus diversity are high. Studies have demonstrated the presence of homosubtypic immunity, where individuals are unlikely to be reinfected with the same subtype within an autumn season. Further, evidence for heterosubtypic immunity exists, whereby immune responses specific for one subtype offer partial or complete protection against related HA subtypes. We utilized a natural experimental system to determine whether homo- or heterospecific immunity could be induced following experimental vaccination. Thirty Mallards were vaccinated with an inactivated H3, H6 or a sham vaccine and after seroconversion were exposed to naturally infected wild conspecifics. All ducks were infected within 2days and had both primary and secondary infections. Overall, there was no observable difference between groups; all individuals were infected with H3 and H10 IAV. At the cessation of the experiment, most individuals had anti-NP antibodies and neutralizing antibodies against H10. Not all individuals had H3 neutralizing antibodies. The isolated H3 IAVs revealed genetic dissimilarity to the H3 vaccine strain, specifically substitutions in the vicinity of the receptor-binding site. There was no evidence of vaccine-induced homosubtypic immunity to H3, a likely result of both a poor H3 immune response in the ducks and H3 immune escape. Likewise, there was no observed heterosubtypic protection related to H6 vaccination. This study highlights the need for experimental approaches to assess how exposure to pathogens and resulting immune processes translates to individual and population disease dynamics.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
Keywords
Anas platyrhynchos, H3, homosubtypic immunity, humoral immunity, immunity, influenza A virus, Mallard
National Category
Ecology Microbiology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-64211 (URN)10.1111/mec.13967 (DOI)000395700600015 ()27997047 (PubMedID)2-s2.0-85013040569 (Scopus ID)
Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2019-08-29Bibliographically approved
Avril, A., Grosbois, V., Latorre-Margalef, N., Gaidet, N., Tolf, C., Olsen, B. & Waldenström, J. (2016). Capturing individual-level parameters of influenza A virus dynamics in wild ducks using multistate models. Journal of Applied Ecology, 53(4), 1289-1297
Open this publication in new window or tab >>Capturing individual-level parameters of influenza A virus dynamics in wild ducks using multistate models
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2016 (English)In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 53, no 4, p. 1289-1297Article in journal (Refereed) Published
Abstract [en]

Disease prevalence in wildlife is governed by epidemiological parameters (infection and recovery rates) and response to infection, both of which vary within and among individual hosts. Studies quantifying these individual-scale parameters and documenting their source of variation in wild hosts are fundamental for predicting disease dynamics. Such studies do not exist for the influenza A virus (IAV), despite its strong impact on the global economy and public health. Using capture-recaptures of 3500 individual mallards Anas platyrhynchos during seven migration seasons at a stopover site in southern Sweden, we provide the first empirical description of the individual-based mechanisms of IAV dynamics in a wild reservoir host. For most years, prevalence and risk of IAV infection peaked at a single time during the autumn migration season, but the timing, shape and intensity of the infection curve showed strong annual heterogeneity. In contrast, the seasonal pattern of recovery rate only varied in intensity across years. Adults and juveniles displayed similar seasonal patterns of infection and recovery each year. However, compared to adults, juveniles experienced twice the risk of becoming infected, whereas recovery rates were similar across age categories. Finally, we did not find evidence that infection influenced the timing of emigration.Synthesis and applications. Our study provides robust empirical estimates of epidemiological parameters for predicting influenza A virus (IAV) dynamics. However, the strong annual variation in infection curves makes forecasting difficult. Prevalence data can provide reliable surveillance indicators as long as they catch the variation in infection risk. However, individual-based monitoring of infection is required to verify this assumption in areas where surveillance occurs. In this context, monitoring of captive sentinel birds kept in close contact with wild birds is useful. The fact that infection does not impact the timing of migration underpins the potential for mallards to spread viruses rapidly over large geographical scales. Hence, we strongly encourage IAV surveillance with a multistate capture-recapture approach along the entire migratory flyway of mallards.

Keywords
avian influenza, epidemiology, host-pathogen dynamics, individual-based monitoring, influenza A virus, multistate capture-recapture, outbreaks, SIR model, waterfowl, zoonosis
National Category
Ecology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-55770 (URN)10.1111/1365-2664.12699 (DOI)000380065600033 ()2-s2.0-84973607340 (Scopus ID)
Available from: 2016-08-26 Created: 2016-08-26 Last updated: 2018-10-24Bibliographically approved
Bengtsson, D., Safi, K., Avril, A., Fiedler, W., Wikelski, M., Gunnarsson, G., . . . Waldenström, J. (2016). Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?. Royal Society Open Science, 3(2), 1-11, Article ID 150633.
Open this publication in new window or tab >>Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?
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2016 (English)In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 3, no 2, p. 1-11, article id 150633Article in journal (Refereed) Published
Abstract [en]

The last decade has seen a surge in research on avian influenza A viruses (IAVs), in part fuelled by the emergence, spread and potential zoonotic importance of highly pathogenic virus subtypes. The mallard (Anas platyrhynchos) is the most numerous and widespread dabbling duck in the world, and one of the most important natural hosts for studying IAV transmission dynamics. In order to predict the likelihood of IAV transmission between individual ducks and to other hosts, as well as between geographical regions, it is important to understand how IAV infection affects the host. In this study, we analysed the movements of 40 mallards equipped with GPS transmitters and three-dimensional accelerometers, of which 20 were naturally infected with low pathogenic avian influenza virus (LPAIV), at a major stopover site in the Northwest European flyway. Movements differed substantially between day and night, as well as between mallards returning to the capture site and those feeding in natural habitats. However, movement patterns did not differ between LPAIV infected and uninfected birds. Hence, LPAIV infection probably does not affect mallard movements during stopover, with high possibility of virus spread along the migration route as a consequence.

National Category
Infectious Medicine Ecology
Research subject
Ecology, Zoonotic Ecology
Identifiers
urn:nbn:se:lnu:diva-49798 (URN)10.1098/rsos.150633 (DOI)000377969000024 ()2-s2.0-84958073847 (Scopus ID)
Available from: 2016-02-16 Created: 2016-02-16 Last updated: 2019-11-28Bibliographically approved
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