Small-scale land-use variability affects Anopheles spp. distribution and concomitant Plasmodium infection in humans and mosquito vectors in southeastern Madagascar

Additional file 1. Individual health assessment form

Causative Agent of Canine Heartworm (Dirofilaria immitis) Detected in Wild Lemurs

The lemurs of Madagascar are threatened by human activities. We present the first molecular detection of canine heartworm (Dirofilaria immitis) in a wild non-human primate, the mouse lemur (Microcebus rufus). Zoonotic D. immitis infection has been associated with clinical pathology that includes serious and often fatal cardiac and pulmonary reactions. With human encroachment and associated increases in free-roaming dog populations in Madagascar, we examined lemurs for zoonotic canid pathogens. D. immitis presents a new potential conservation threat to lemurs. We highlight the need for wide-ranging and effective interventions, particularly near protected areas, to address this growing conservation issue

Mapping the social network : tracking lice in a wild primate (Microcebus rufus) population to infer social contacts and vector potential

Peer reviewe

Teeth, Sex, and Testosterone : Aging in the World's Smallest Primate

Peer reviewe

Host-related and environmental factors influence long-term ectoparasite infestation dynamics of mouse lemurs in northwestern Madagascar

Parasite infestations depend on multiple host-related and environmental factors. In the case of ectoparasites, which are exposed to the environment beyond the host, an impact of climate, expressed by seasonal or yearly variations, can be expected. However, long-term dynamics of ectoparasite infestations are rarely studied in nonhuman primates. We investigated the yearly variations in ectoparasite infestations of two small primates, the gray (Microcebus murinus) and the golden-brown (Microcebus ravelobensis) mouse lemur. For a more comprehensive evaluation, we also analyzed the potential effects of yearly and monthly climatic variation (temperature, rainfall) in addition to habitat, host sex, age, species, and body mass, on ectoparasite infestation. Individuals of both host species were sampled in two study sites within the Ankarafantsika National Park in northwestern Madagascar during several months (March–November) and across 4 years (2010, 2011, 2015, 2016). Our results show significant monthly and yearly variations in the infestation rates of three native ectoparasite taxa (Haemaphysalis spp. ticks, Schoutedenichia microcebi chigger mites, Lemurpediculus spp. sucking lice) and in ectoparasite species richness in both mouse lemur species. In addition, significant impacts of several host-related (species, sex, body mass) and environmental factors (habitat, temperature, rainfall) were found, but with differences in relevance for the different parasite taxa and partly deviating in their direction. Although some differences could be attributed to either permanent or temporary presence of the parasites on the host or to ecological differences between the host species, the lack of specific knowledge regarding the life cycle and microhabitat requirements of each parasite taxon precludes a complete understanding of the factors that determine their infestation dynamics. This study demonstrates the presence of yearly and monthly dynamics in lemur–parasite interactions in tropical, seasonal, dry deciduous forests in Madagascar, which call out for broad ecological long-term studies focusing both on primate hosts and their parasites

Molecular phylogenetics of the sucking louse genus Lemurpediculus (Insecta: Phthiraptera), ectoparasites of lemurs, with descriptions of three new species

Sucking lice live in intimate association with their hosts and often display a high degree of host specificity. The present study investigated sucking lice of the genus Lemurpediculus from six mouse lemur (Microcebus) and two dwarf lemur (Cheirogaleus) species endemic to the island of Madagascar, considered a biodiversity hotspot. Louse phylogenetic trees were created based on cytochrome C oxidase subunit I (COI), elongation factor 1α (EF1α) and internal transcribed spacer 1 (ITS1) sequences. While clustering according to host species was generally observed for COI and ITS1, suggesting high host specificity of the examined lice, EF1α sequences alone did not distinguish between lice of different Microcebus species, possibly due to rather recent divergence. As bootstrap support for basal tree structure was rather low, further data are necessary to resolve the evolutionary history of louse-mouse lemur associations. Three new species of sucking lice are described: Lemurpediculus zimmermanni sp. Nov. From Microcebus ravelobensis, Lemurpediculus gerpi sp. Nov. From Microcebus gerpi, and Lemurpediculus tsimanampesotsae sp. Nov. From Microcebus griseorufus. These new species are compared with all known congeneric species and identifying features are illustrated for all known species of Lemurpediculus

Molecular phylogenetics of the sucking louse genus Lemurpediculus (Insecta: Phthiraptera), ectoparasites of lemurs, with descriptions of three new species

Sucking lice live in intimate association with their hosts and often display a high degree of host specificity. The present study investigated sucking lice of the genus Lemurpediculus from six mouse lemur (Microcebus) and two dwarf lemur (Cheirogaleus) species endemic to the island of Madagascar, considered a biodiversity hotspot. Louse phylogenetic trees were created based on cytochrome C oxidase subunit I (COI), elongation factor 1α (EF1α) and internal transcribed spacer 1 (ITS1) sequences. While clustering according to host species was generally observed for COI and ITS1, suggesting high host specificity of the examined lice, EF1α sequences alone did not distinguish between lice of different Microcebus species, possibly due to rather recent divergence. As bootstrap support for basal tree structure was rather low, further data are necessary to resolve the evolutionary history of louse-mouse lemur associations. Three new species of sucking lice are described: Lemurpediculus zimmermanni sp. Nov. From Microcebus ravelobensis, Lemurpediculus gerpi sp. Nov. From Microcebus gerpi, and Lemurpediculus tsimanampesotsae sp. Nov. From Microcebus griseorufus. These new species are compared with all known congeneric species and identifying features are illustrated for all known species of Lemurpediculus

Citizen Science as an Approach for Responding to the Threat of 'Anopheles stephensi' in Africa

Even as novel technologies emerge and medicines advance, pathogen-transmitting mosquitoes pose a deadly and accelerating public health threat. Detecting and mitigating the spread of Anopheles stephensi in Africa is now critical to the fight against malaria, as this invasive mosquito poses urgent and unprecedented risks to the continent. Unlike typical African vectors of malaria, An. stephensi breeds in both natural and artificial water reservoirs, and flourishes in urban environments. With An. stephensi beginning to take hold in heavily populated settings, citizen science surveillance supported by novel artificial intelligence (AI) technologies may offer impactful opportunities to guide public health decisions and community-based interventions. Coalitions like the Global Mosquito Alert Consortium (GMAC) and our freely available digital products can be incorporated into enhanced surveillance of An. stephensi and other vector-borne public health threats. By connecting local citizen science networks with global databases that are findable, accessible, interoperable, and reusable (FAIR), we are leveraging a powerful suite of tools and infrastructure for the early detection of, and rapid response to, (re)emerging vectors and diseases

Evidence for a role of Anopheles stephensi in the spread of drug- and diagnosis-resistant malaria in Africa

Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Here, using a prospective case-control design, we investigated the role of An. stephensi in transmission following a malaria outbreak in Dire Dawa, Ethiopia in April-July 2022. Screening contacts of patients with malaria and febrile controls revealed spatial clustering of Plasmodium falciparum infections around patients with malaria in strong association with the presence of An. stephensi in the household vicinity. Plasmodium sporozoites were detected in these mosquitoes. This outbreak involved clonal propagation of parasites with molecular signatures of artemisinin and diagnostic resistance. To our knowledge, this study provides the strongest evidence so far for a role of An. stephensi in driving an urban malaria outbreak in Africa, highlighting the major public health threat posed by this fast-spreading mosquito

Vanhenemisen ekologia : ikääntyminen hiirimakien (Microcebus rufus) luonnonvaraisessa populaatiossa

Mouse lemurs are the world s smallest primates and a model species for ancestral primates that lived 55 million years ago. In captive conditions, mouse lemurs live over six times longer than similarly sized mice and have been found to exhibit many symptoms of human senescence, including Alzheimer s-like neurodegeneration. These traits make captive mouse lemurs an exemplary model for aging. Despite this, to date no study has examined the aging process in wild mouse lemurs. This thesis addresses multidisciplinary questions relating to mouse lemur aging and life history. Through mark-recapture data and a combination of field and laboratory techniques I examine the aging process in wild brown mouse lemurs (Microcebus rufus). To estimate ages of individual wild mouse lemurs a technique was developed using dental wear. I found that in their natural habitat these tiny primates live up to 8 years of age, well past the captive age of senescence (5 yrs). Among old individuals, both males and females are represented, and unlike other polygamous vertebrates age-dependent survival rates do not differ between sexes. With the ages of wild mouse lemurs identified, other age-related factors such as hormone levels and parasite loads were subsequently examined. Contrary to findings in captivity no observable physical symptoms of senescence were found in old mouse lemurs, i.e. over the age of five. Further, new findings highlight mouse lemurs as an exception to many assumptions of mammalian physiology. In this study, testosterone levels were found to be comparable in both males and females, potentially providing an explanation for the lack of difference in survival rates between sexes. Testosterone and DHEA-S, two hormones typically found to decrease with age, did not differ between young and old lemurs. However, cortisol, the stress hormone, did decrease with age in male mouse lemurs, but not in females. Differences in immunity with age were examined indirectly via parasite dynamics. Specifically, I described the ectoparasites found on brown mouse lemurs, and created and implemented a novel method which allows the tracking of the natural flow of parasites between known individuals in a wild. This method revealed that parasite movement between lemurs suggests a much more complex social network than indicated by trapping, provided new insight about how parasites/pathogens move among wild populations, and revealed that only a few individual lemurs could be responsible for population-wide louse-borne epidemic. In addition to shedding light on the social behavior of mouse lemurs, I used the presence of ecto- and endoparasites as an indicator of immune health in young and old individuals, exposing a decline in endoparasites with age, but not in ectoparasites. Hormone measures and parasite loads were also employed to test the immunocompetence handicap hypothesis (ICHH) (which implicates testosterone as a cause for immunosuppression and hence higher parasite intensities) in both sexes. Contrary to the ICHH no correlation between testosterone and parasite intensities was found; however, when cortisol and testosterone positively co-varied higher parasite loads were observed in both sexes. In conclusion, in the search for a better understanding of the aging process in wild brown mouse lemurs I examined the multifaceted physiological transformations (parasitological, endocrinological, and dental wear). This research produced novel, replicable methodologies and findings with wide-reaching implications that extend beyond aging and challenge some of the previously-held assumptions of mammalian biology.Madagaskarin endeemiseen lajistoon kuuluvat hiirimakit ovat maailman pienimpiä nisäkkäitä. Nämä hiirenkokoiset makit voivat elää vankeudessa jopa 13-vuotiaiksi, mikä on noin kuusi kertaa kauemmin kuin muut vastaavankokoiset nisäkkäät. Viiden vuoden jälkeen nämä pienet nisäkkäät alkavat kuitenki ilmentää samoja vanhenemiseen liittyviä piirteitä kuin ihmisetkin, joihin lukeutuvat muun muassa hermoston rappeutuminen (Alzheimerin kaltaiset neurodegeneratiiviset sairaudet), kaihi, kuuroutuminen, liikuntakyvän aleneminen, sekä harmaantuminen. Näistä piirteistä johtuen hiirimakeja on aletu käyttää yhä suuremmassa määrin mallina kädellisten vanhenemistutkimuksissa. Tähän saakka ei olla tiedetty miten pitkään luonnonvaraiset hiirimakit pystyvät elämään ja alkavatko ne ilmentää näitä vanhuuteen liittyviä piirteitä, joita tavataan vankeudessa eläviltä yksilöiltä. Tämä väitöskirjatyö keskittyy selvittämään Madagaskarin, Ranomafanan luonnonvaraisen hiirimakipopulaation (Microcebus rufus) vanhenemisprosesseja sekä kenttä-, että laboratoriotutkimuksin käyttämällä iän kanssa korreloivia piirteitä kuten hormooneja, loismääriä, sekä hampaiston kuntoa iänmäärityksissä. Hampaat kuluvat iän myötä ja saattavat jopa irrota myöhemmällä iällä kokonaan. Ottamalla hammasmuotit merkityiltä luonnonvaraislta hiirimakiyksilöiltä ja vertaamalla niitä myöhempiin aikapisteisiin oli mahdollista arvioida näiden luonnonvaraisten hiirimakien ikää. Tutkimuksissa kävi ilmi, että luonnonvaraiset hiirimakit pystyvät elämään jopa yli kahdeksan vuotiaiksi, mikä on kolme kertaa luultua kauemmin. Itseasiassa yli 14 prosenttia populaatiosta osoittautui vanhoiksi yksilöiksi (yli viisivuotiaita), joilta puuttuivat kaikki vankeudessa eläviltä yksilöiltä tavattavat vanhuuden oireet. Tämä tulos kyseenalaistaa siten aiemmin vankeudessa eläneiltä yksilöiltä saadut tukimustulokset hiirimakien luontaisesta vanhenemisesta. Ihmisellä, kuten suuremmalla osalla moniavioisista selkärankaislajeista, koiraat kuolevat naaraita aiemmin. Tämä piirre on usein yhdistetty koiraiden korkeisiin testosteronipitoisuuksiin. Tämän väitöskirjatutkimuksen mukaan näyttäisi kuitenkin siltä, että hiirimakeilla sekä naaraiden että koiraiden kuolevuus on sama. Tämä näyttäisi korreloivan testosteronipitoisuuksien kanssa, jotka yllättäen osoittautuivat samoiksi, sekä hiirimakinaaraiden että -koiraiden välillä. Tämän lisäksi luonnonvaraisilta hiirimakeilta ei näyttänyt löytyvän korrelaatiota iän ja testosteronin tai muiden iäkäriippuvaisten hormoonien (DHT and DHEA-S) pitoisuuksien väliltä, mikä on toisin kuin mitä ihmisiltä ja vankeudessa eläviltä hiirimakeilta tavataan. Tutkimus kuitenkin osoitti, että stressihormoonin, korttisolin, määrä väheni hiirimaki koirailla iän myötä, mikä saattaa edesauttaa koiraiden pitempää selviytymistä. Testosteronin on ehdotettu alentavan immuunipuolustusta. Tutkittaessa immuunipuolustuksen epäsuoriaparametreja (ulko- ja sisäloisia) väitöskirjatyössä kävi ilmi, että loiskuorma näytti olevan suurempi koirailla huolimatta samoista testosteronipitoisuuksista eri sukupuolten välillä. Tarkemman kuvan saamiseksi yksittäisiä loisia merkittiin hiirimakiyksilöllille ominaisilla värikoodilla, minkä avulla pyrittiin seuraamaan loisten liikkumista eri yksilöiden välillä. Koska loiset pystyvät leviämään ainoastaan suorassa yksilöiden välisessä kontaktissa, näiden merkittyjen loisten seuraaminen mahdollisti samalla hiirimakien sosiaalisen käyttäytymisen seuraamisen, mikä muuten olisi erittäin vaikeaa kun kyseessä on pieni, yöaktiivinen, puussaelävä laji. Tämä tutkimus valoittaa näin ollen lisäksi parasiittien ja patogeenien liikkumista populaation sisällä ja mahdollistaa siten uusien mallien kehittämisen niiden dynamiikasta. Tutkimuksessa käytetyt useiden tekniikoiden yhdistelmät (elävänäpyynti, hammasmuotit, lois- ja hormoonianalyysit) mahdollistavat uudenlaisen tutkimuksen luonnonvaraisessa eläinpopulaatiossa. Tämä väitöskirjatyö yhdistää monitieteellisen tutkimuksen, kyseenalaistamalla samalla vanhoja käsityksiä nisäkkäiden biologiasta, sekä tuomalla uutta tutkimustietoa, jotta ymmärtäisimme paremmin luonnonvaraisten eläinten luontaisia elinolosuhteita