Were human-introduced diseases the responsible for Pleistocene-Holocene megafaunal extinctions? First evidence from South America

Diverse hypotheses have been proposed with the aim to explain the extinction of Late Pleistocene/Holocene mammals, including the Megafauna from America. Some authors support that human being was the direct responsible of extinction by means of intensive hunting, as proposed by the “blitzkrieg” or overkilling hypothesis. However, evidence is not conclusive. As is well known by biologists, exotic diseases may play an important role in local extinction of diverse vertebrates. On this basis, some speculated that the arrival of man may also have introduced new diseases that may have played an important role on native mammals, especially megafaunal populations, probably constituting a key factor on their extinction. Recent findings of the parasite Fasciola hepatica in endemic deer from Holocene sites in Patagonia (and also probably from camelids in Peru) previous to Hispanic colonization constitute indirect evidence that may sustain this hypothesis. Because one of the main definite host of this parasite are humans, this potential disease may have been introduced by human populations as hosts and then disperse through the entire continent, as evidenced by the finding of Fasciola hepatica in Patagonia. Its presence in endemic deer and camelids previous to Hispanic colonization, reinforces the proposal that human-related diseases may have played some role in Late Pleistocene extinction of large native mammals.

A rare case of hydatid cyst of the interventricular septum

A Hydatid disease or Echinococcosis is a zoonotic disease caused by the larvae (metacestode) of the cestode species of the genus Echinococcus. Humans are the accidental hosts of the diseases; they usually acquire it from canines; which are the definite host. It can present with systemic cyst, while cardiac manifestation of the disease is rare, due to contractile property of the heart’s muscle fiber which provide resistance. In this case report, the patient is diagnosed with hydatid cyst in the inter ventricular septum; it’s diagnosis and its successful treatment with surgery and albendazole. As, inter ventricular septum hydatid cyst occurs in only 0.5-2% cases, it’s a unique case and its successful treatment and diagnosis can help the physicians in the future to treat a similar case as this.

The first definite record of Sinomegoura citricola (van der Goot, 1917) (Hemiptera: Aphididae) occurring on Ilex rotunda (Aquifoliaceae)

In April 2018, the occurrence of Sinomegoura citricola was recorded on Ilex rotunda (Aquifoliaceae) in Japan. Both aphid identification with mounted specimens and rearing experiments with the plant shoots revealed that I. rotunda is a definite host for S. citricola. This is believed to be the first study to report a species of the family Aquifoliaceae as a certain host plant of S. citricola, emphasizing that the aphid is a polyphagous species.

Diferensiasi Stadium Takizoit-Bradizoit pada Toxoplasma gondii

Toxoplasma gondii is an intracellular parasite whose definite host is cat or felidae and intermediate host is human orother mammals. It causes congenital and acquisita toxoplasmosis. Infection with this apicomplexan parasite results inits dissemination throughout its host via the tachyzoite life stage. After dissemination, these tachyzoites differentiateinto bradyzoites within cyst and remain latent. These bradyzoites can transform back into tachyzoites and inimmunosupressed individuals this often results in symptomatic disease. Both tachyzoites and bradyzoites develop intissue culture and this crucial differentiation event can be studied. Interferon gamma (IFN ) is the main mediator intachyzoite-bradyzoite differentiation.

Description Between Cats Exposure with Toxoplasmosis Disease on Cats Owner and Not- Cats Owner in Mulyorejo Subdistrict, Surabaya City

Toxoplasmosis is an infectious disease caused by Toxoplasma gondii that transmitted from animals to humans. Actually, the symptoms of toxoplasmosis are asymptomatic with non-spesific and similar to other diseases. Cats are definite host of Toxoplasma gondii. The feces from infected cat contains million oocysts and infective to humans. Detection of toxoplasmosis in human can be done with a serological test to see the levels of immunoglobulin M (IgM) and immunoglobulin G (IgG) anti-toxoplasmosis. The purpose of this study was to identification toxoplasmosis and describe between exposure from cats with toxoplasmosis disease to people who own and don’t own cats in Mulyorejo Subdistrict, Surabaya City. This study was an descriptive observational research with cross sectional design in two populations. The subject was choosen randomly. This study was done to 25 respondents as cat owner and 25 respondents who weren’t. Data was collected from questionnaire and respondent’s blood sample. Prevalence of toxoplasmosis in cat owner 52% and 48% in not-cat owner. Crosstabulation showed that there were similar tendency between variables of feral cats, number of feral cats, and presence of cat’s feces to toxoplasmosis disease on cats owner and not-cats owner in Mulyorejo Subdistrict, Surabaya City.It is expected that the community is able to notice the presence of feral cats and cat’s feces around it to avoid the risk of infection from Toxoplama gondii.Keywords: Cats owner, Not-cats owner, Cat, Toxoplasmosis

Identification of the plague reservoir in an endemic area of Zambia

Yersinia pestis, the bacterial agent of plague, is primarily a parasite of wild rodents that persists in permanent, discrete enzootic foci throughout the world. The disease is transmitted in humans by bites from fleas of wildlife rodent species. Therefore surveillance is the ultimate public health solution through plague detection in domestic dogs, other carnivores and wild rodents. The investigations of die-offs amongst plague-susceptible colonial rodents are also significant to determine the presence of Y. pestis in a susceptible population.This study details the identification of the plague reservoir in a suspected endemic area of Zambia. The study was undertaken through rodent investigation for the presence of Y. pestis. A total of 105 rodents were sampled routinely and during a suspected plague period. On dissection 4 (3.81%, 95% CI: 1.23−10.0) rodents sampled during an outbreak showed signs of spleen enlargement. The blood, liver, lymph nodes and spleen of each rodent were subjected to culture on 6% sheep blood agar and MaCconkey agar. Colonies obtained were identified as Y. pestis by colony morphologic features, biochemical profiles, mouse inoculation assay and polymerase chain reaction (PCR). The PCR primers used targeted the Y. pestis plasminogen activator gene, chromosomal ferric iron uptake regulation gene and the outer membrane protein B gene.The isolates were also subjected to antibiotic sensitivity tests using the disk diffusion method on Mueller-Hinton agar with sensitivity being observed with ampicillin, amoxicillin, chloramphenicol, gentamycin, streptomycin, tetracycline and trimethoprim-sulfamethoxazole. The findings, identifies a natural reservoir of Y. pestis in Zambia providing the public health officials with a definite host for the control strategy.

A SEM study of the reindeer sinus worm (Linguatula arctica)

Pentastomids are a group of peculiar parasitic arthropods, often referred to as tongue worms due to the resemblance of some species to a tongue. Linguatula arctica is the sinus worm of the reindeer (Rangifer tarandus), being the only pentastomid to have a direct life cycle and an ungulate as a definite host. Here, the surface structures and internal anatomy of adult L. arctica are described as seen by scanning electron microscopy (SEM). Sinus worms were collected in the winter 1991-92 in Finnish Lapland. Paranasal cavities of about 80 reindeer were examined and 30 sinus worms were found. The sinus worms had typical Linguatula sp. morphology, being paddle-shaped, transparent, pale yellow, dorsoventrally flattened and pseudosegmented with a long tapering end. Present at the anteroventral part of the cephalothorax was an oral opening with a large, conspicuous, head-like papillar structure. Bilaterally, on both sides of this opening, was a pair of strong curved hooks. The cephalothorax and abdomen had a segmented appearance, as they showed distinct annulation. There was a small cup-shaped sensory organ present at the lateral margin on each annula. The posterior edge of each annula was roughened by tiny spines projecting backwards. Throughout the cuticular surface, small, circular depressions that represented the apical portion of chloride cells. The genital opening of the male was located medioventrally between the tips of the posterior pair of hooks, and that of the female posteroventrally and subterminally. In both sexes, the genital opening was bilaterally flanked by papillar (in males) or leaf-like (in females) structures. One copulating couple was present, with the male attached to the posteroventral part of the female with its anteroventral hooks and papillae. Several structures typical of arthropods and other pentastomids were identified. Because SEM allows only surfaces to be studied, the morphology and especially the sense organs of L. arctica remain obscure. Transmission electron microscopy should be employed to gain more information about this fascinating creature and its origin.Abstract in Finnish / Yhteenveto:Elektronimikroskooppinen tutkimus poron kielimadosta (Linguatula arctica) Pentastomida (matoäyriäiset) ovat ryhmä erikoisia parasiitteihin kuuluvia niveljalkaisia. Niitä kutsutaan usein kielimadoiksi, sillä monet ryhmään kuuluvista lajeista ovat muodoltaan kielimäisiä. Linguatula arctica, poron kielimato, on poron nenäonteloon liittyvissä sivuonteloissa elävä loinen. Se on ainoa tunnettu matoäyriäinen, jolla on sorkkaeläin pääisäntänä ja suora (ilman väli-isäntää tapahtuva) elämänkierto. Tässä tutkimuksessa tarkasteltiin L. arctica -loisen pinta- ja sisärakenteita pyyhkäisyelektronimikroskoopin avulla. Loiset kerättiin Suomen lapista talvella 1991–92. Nenän sivuontelot tutkittiin loisten varalta noin 80 porosta, ja niistä löydettiin yhteensä 30 kielimatoa. Kielimatojen ulkonäkö oli tyypillinen Linguatula-suvun loisille. Ne olivat melanmuotoisia, läpikuultavia, vaalean kellertäviä, litteitä, ne vaikuttivat jaokkeisilta ja niillä oli pitkä loppua kohden kapeneva häntä. Suu sijaitsi vatsapuolella lähellä etupäätä, ja suuhun liittyneenä oli selvästi erottuva päämäinen uloke. Suuaukon tuntumassa, suuaukon molemmilla puolilla oli pari voimakkaasti kehittyneitä kynsimäisiä koukkurakenteita. Kielimadon ulkopinta koostui annulaarisista rakenteista, mistä johtuen se vaikutti jaokkeiselta. Loisen sivuissa, kunkin jaokkeen reunassa, oli tuntoelin, joka näkyi pyyhkäisyelektronimikroskoopilla kuppimaisena syvennyksenä. Jaokerenkaiden takareuna oli pienten, taaksepäin suuntautuneiden kitiinipiikkien karhentama. Koko ulkopinnan alueella nähtiin pieniä, pyöreitä painautumia, joiden todettiin olevan loisen pintaan avautuva kärkiosa niin kutsutuista kloridisoluista. Koiraskielimadon sukuaukko sijaitsi vatsapuolella takimmaisen koukkuparin kärkien tasolla, naaraan vastaavasti vatsapuolella lähellä takapäätä. Sekä koiraalla että naaraalla nähtiin sukuaukon molemmissa reunoissa ulokkeet, jotka koiraalla olivat nystymäiset ja naaraalla lehtimäiset. Tutkitussa materiaalissa todettiin yksi paritteleva kielimatopari. Tutkimuksessa voitiin tunnistaa useita niveljalkaisille ja matoäyriäisille tyypillisiä rakenteita. Koska pyyhkäisyelektronimikroskoopin avulla voidaan tutkia ainoastaan pintarakenteita, erityisesti tuntoelimien rakenteista saatu informaatio jäi pinnalliseksi. Läpivalaisu- eli transmissioelektronimikroskoopin avulla tästä kiehtovasta eliöstä ja sen alkuperästä olisi mahdollista saada lisää tietoa.Abstract in Swedish / Sammandrag:En elektronmikropisk studie av renens bihålemask (Linguatula arctica) Pentastomiderna är en grupp egendomliga, parasitiska ledfotingar ofta beskrivna som tungmaskar beroende på att några arter är tunglika. Linguatula arctica är renens (Rangifer tarandus) bihålemask, den enda pentastomid som har en direkt livscykel och ett klövdjur som slutvärd. Nedan beskrivs ytstrukturer och inre morfologi av könsmogna L. arctica sedda med skanningelektronmikroskop (SEM). Bihålemaskarna insamlades vintrarna 1991 och 1992 i Finlands Lappland. De paranasala håligheterna på ca 80 slaktade renar undersöktes och 30 bihålemaskar upptäcktes. Bihålemaskarna hade för Linguatula arterna typisk morfologi. De var paddelformade, delvis genomskinliga, svagt gulaktiga, tillplattade och skenbart segmenterade med en lång smal bakkropp. På framkroppens undre sida fanns en munöppning med ett stort tydligt huvudliknande utskott. På båda sidor om denna öppning fanns ett par starka krökta hakar. Framkroppen och bakkroppen hade ett segmenterat utseende, emedan ytan hade tydlig annulation. Det fanns små koppformade känselorgan på sidan av varje annula. Bakkanten av varje annula var försedd med små bakåt riktade taggar. Hela ytan (kutikulan) var full av små, runda fördjupningar, som var den synliga delen av kloridcellerna. Hanens genitalöppning var på undre sidan mellan det bakre paret av hakarna och honans i spetsen på bakkroppen. Genitalöppningen hos hanen hade lateralt papiller och honans bladlika strukturer. Ett kopulerande par där hanen hade fäst sig med hakar och papiller vid honans bakkropp observerades. Flera strukturer karakteristiska för ledfotingar och pentastomider identifierades. Emedan endast ytor kan studeras med SEM förblir morfologin, speciellt känselorganens, okänd. Undersökningar med transmissionselektronmikroskop borde göras för att få mer information om denna fascinerande varelse och dess ursprung.

Survey of rats and mice and their ectoparasites in relation to cultivated areas in the vicinity of Alexandria governorate, Egypt

SUMMARYSix species and subspecies of rats and mice, Arvicanthis niloticus, Rattus norvegicus, R. rattus frugivorus, R. rattus alexandrinus, R. rattus rattus, and Mus musculus, were found associated with cotton, wheat, maize, sugar-cane, vegetables, fruit and berseem in the vicinity of Alexandria, Egypt. A. niloticus comprised 42·2% of all species collected. Maize, wheat, cotton and berseem were infested most. The lowest infestation was recorded in the fruit fields. Infestation in sugar-cane and vegetables was intermediate. R. norvegicus, M. musculus, R. rattus frugivorus, R. rattus alexandrinus and it. rattus rattusformed 23·9, 16·7, 10·4, 4·2 and 2·7% of the species collected respectively. Of the seven crops investigated, only two (cotton, wheat) were not infested with R. rattus rattus, but all were plagued with some species of rodents. The abundance of these rodents in fields seemed to be positively correlated with temperature and relative humidity. Winter represents a definite off-season for all species recorded.Six species of fleas (Xenopsylla cheopis, Nosopsyllus fasciatus, Ctenocephalides felis felis, Leptopsylla segnis, Pulex irritans and Echidnophaga gallinacea), three of sucking lice (Polyplax abyssinica, P. spinulosa and Hoplopleura capitosa), five of parasitic mites (Ornithonyssus bacoti, Laelaps echidnina, L. keegani, Androlaelaps zulu and Haemolaelaps sp.) and the tick Rhipicephalus sanguineus sanguineus were recovered from the rodents. Fleas (especially X. cheopis) and lice generally showed a certain degree of host specificity. A close relationship has been shown to exist between the abundance of fleas and lice and the abundance of some rodent hosts and climate. However, no definite host specificity or relation to climate was shown by infestation with mite species. Only B. sanguineus sanguinetie was recovered from S. rattus frugivorus during July, October and December; from R. rattus alexandrinus during November; and from R. rattus rattus during September. Its rate of infestation did not exceed one specimen per rodent host.

Biological Observations on some Thynnids of Western Patagonia

During a survey for whitegrub parasites, six Thynnid species were found in parts of western Patagonia and studied in varying degrees of detail.Definite host records are established for Elaphroptera scoliaeformis (Hal.), E. (Paralycus) sp. near nigripennis (Smith) and Pseudelaphroptera brevipilosa Durán, which are solitary external parasites of the mature larvae of Aulacopalpus pilicollis (Fairm.) (Rutelinae), Macrosoma glacialis (F.) (Melolonthinae) and Adioristus acuminatus Hust. (Curculionidae), respectively.No adult feeding was observed during the mating flight of E. scoliaeformis and E. sp. near nigripennis, but pairs of P. brevipilosa and Ornepetes semicincta Turner fed extensively on flower heads of Umbelliferae. Some evidence is presented suggesting that at the conclusion of the mating flight the winged males tend to return the apterous females to the sites where they picked them up.Hosts are permanently paralysed and malaxated before eggs are laid on them. The eggs of the two Elaphroptera species are placed parallel to the longitudinal axis of the host, on the mid-ventral line of abdominal segments two to seven. In the case of P. brevipilosa, the egg is lightly cemented by its caudal end at an angle of about 45 degrees to the host surface, the attachment being near the spiracular line of the host and between the third thoracic and sixth abdominal segments.There are five larval instars. The larvae do not normally move over the host surface. In the first four instars feeding is by suction, but the fifth-instar larva tears a hole in the host in the region of the earlier feeding punctures. The film of liquid with which the larva is bathed is produced from its posterior extremity and is not exuded from the feeding puncture. Cocoons of two types may be recognised, corresponding to the sexes, the female type being the shorter and of more rigid construction.E. scoliaeformis, E. sp. near nigripennis, and P. brevipilosa have a single generation a year. The period from egg deposition to cocoon formation is generally covered in three weeks, and at least nine months are spent in the cocoon as a mature larva or prepupa. Adults probably live up to two months.The only natural enemies observed were a Bombyliid of the genus Acrophthalmyda and a Carabid predator, Cnemacanthus sp., attacking the cocoon stages of E. sp. near nigripennis. The adult of this Thynnid is also attacked by a mimicking Asilid fly, Lycomya germainii Big.The function of the mating flight and the economic value of members of the Thynnidae as controlling agents for Scarabaeid pests are briefly discussed.