Philander Opossum Research Articles

The Reproductive Cycles of Three Species of Opossums and Other Mammals in the Panama Canal Zone

Data on the reproductive cycles of Didelphis marsupialis, Marmosa robinsoni , and Philander opossum in the Panama Canal Zone are presented, and the reproductive patterns of an additional 42 species of Panamanian mammals representing seven orders are reviewed. The three species of opossums breed seasonally, and females of D. marsupialis, P. opossum , and possibly M. robinsoni are polyestrous. Breeding in D. marsupialis and P. opossum began in late January and in M. robinsoni in late March in 1967. Females of each species are anestrous in October through January or longer in the case of M. robinsoni . Litter size is largest in M. robinsoni and smallest in P. opossum . Adult males of each species probably are reproductively active throughout the year. Considering all 45 species, reproductive activity, as evidenced by the presence of pregnant or lactating females, is highest in March and April (the latter part of the dry season) and lowest in August through November (middle to late wet season). Twenty-three species are known to breed seasonally, and in these species major periods of copulation occur in November and January and major birth peaks in March–April and July–August. In many species, initiation of reproductive activity appears to be stimulated by the cessation of heavy rains. Most species probably produce their young when food resources are highest. There is no evidence that closely related species stagger their breeding seasons to avoid interspecific competition for limited resources.

Ecologic studies of Venezuelan encephalitis virus in southeastern México. IV. Infections of wild mammals.

In endemic VE virus habitats at Sontecomapan and nearby Arroyo Agrio, Veracruz, México, four species of wild mammals were infected, based on isolation of virus, and six species probably were infected based on antibody tests. Virus was isolated at Sontecomapan during August 1963 from tissues or blood of two opossums (Didelphis marsupialis and Philander opossum) and one bat (Artibeus turpis), and during May 1966 from another bat (Carollia subrufa). Hemagglutination-inhibition (HI), neutralization (N), or complement-fixation (CF) tests with VE virus detected antibodies at Sontecomapan in these mammals and also in Glossophaga bats, Peromyscus mice, Rattus rats, a rabbit, a raccoon, and a weasel, and in endemic habitats at Minatitlan, Veracruz, in Sigmodon cotton rats. The averages of positive-HI prevalences were .43 for wild terrestrial mammals and .17 for bats. Opossums and Artibeus jamaicensis bats were inoculated subcutaneously with VE virus in the laboratory and found to develop viremia within 2 or 3 days, which lasted through the 4th day after inoculation. Detectable N and HI antibodies, but not CF, appeared in serum of opossums within 9 to 30 days and HI antibody in plasma of bats within 10 to 35 days.

Studies on enteric bacterias in the lower amazon region: I. Serotypes of Salmonella isolated from wild forest animals in pará state, Brazil

Twenty-seven strains of Salmonella were isolated from 1,380 wild animals trapped in uninhabited forest in the Lower Amazon Region, Pará, Brazil, following culture of rectal and cloacal swabs. S. san-diego was isolated from 1 marsupial ( Philander opossum); 5 rodents (3 Oryzomys capito and 2 Pröchimys guyannensis) and 14 lizards ( Ameiva ameiva ameiva). S. morehead was recovered from 2 rodents ( O. capito); one edentate ( Choloepus didactylus) and 2 lizards ( Ameiva a. ameiva). S. christiansborg and S. wassenaar : single isolations were made from Ameiva a. ameiva. The importance of wild animal reservoirs in the epidemiology of salmonellosis is discussed, particularly in areas newly colonized by man.

The placenta of the four-eye opossum (Philander opossum).

AbstractThe placental membranes of the four‐eyed opossum were studied by light and electron microscopy. The individual fetuses in each uterus were surrounded by amnion, had allantoic sacs of approximately the same size as each fetus, and were situated in a common yolk sac cavity. The extent of the choriovitelline placenta was marked by a prominent sinus terminalis, and at this margin there was a region where the trophoblast cells penetrated folds of the endometrium. Elsewhere the choriovitelline placenta was closely applied to the uterine epithelium along most of its surface, but the microvilli of the two epithelia did not interdigitate. Numerous inclusion bodies were seen in the trophoblast of both the choriovitelline and bilaminar omphalopleure portions of the placenta, but the aggregates were larger in the latter. The endoderm cells of the choriovitelline placenta had extensive endoplasmic reticulum and numerous mitochondria, but did not have conspicuous absorption canaliculi.Placentation in the four‐eyed opossum appears to represent a progressive advance over that of the Virginia opossum both in confluence of the yolk sacs of the fetuses and in having a region of penetration of the maternal endometrium by trophoblast.

Notes on Reproduction and Development in the Four-Eyed Opossum, Philander opossum, in Nicaragua

Notes on Reproduction and Development in the Four-Eyed Opossum, Philander opossum, in Nicaragua

Besnoitia darlingi (Brumpt, 1913) in Panama

SYNOPSIS. Besnoitia darlingi (Brumpt, 1913) Mandour, 1965 has been rediscovered in the common opossum Didelphis marsupialis in the Republic of Panama. A strain (D3) has been established in laboratory white mice. Proliferative crescents of the D3 strain are 6.1 (range 6.0‐9.0) by 2.1 (range 1.7‐4.0).Mouse‐adapted B. darlingi produced acute, fatal infections in white mice, hamsters, 14 marmosets (Saguinus geoffroyi), 2 squirrels (Sciurus variegatoides and S. granatensis), a woolly opossum (Caluromys derbianus) and a four‐eyed opossum (Philander opossum) It probably produced chronic infections (cysts) in 2 wild‐caughtopossums (Didelphis marsupialis) and one lizard (Ameiva ameiva). Animals in which induced infection could not be found after inoculation with trophozoites of mouse‐adapted B. darlingi were: 2 adult and 2 new‐born guinea pigs, laboratory rats, 1 night monkey (Aotus trivirgatus), 2 rhesus monkeys (Macacca mulatta), one iguana (Iguaanaiguana) and 2 baby caimans (Caiman sclerops).

Leptospirosis in Nicaragua: preliminary report on the first year of study.

SummaryResults of one year's study of leptospirosis in Nicaraguan wild and domestic animals is presented. Leptospirae of the canicola group were isolated from Urocyon cinereoargenteus, Spilogale putorius and Conepatus semistriatus; of the pyrogenes group from Oryzomys caliginosus; serotypes rama and abramis and leptospirae of hebdomadis and autumnalis groups from Philander opossum. These investigations support the view that wild animals are unimportant in the episootiology of clinical bovine leptospirosis.

An outbreak of leptospirosis among U. S. army troops in the Canal Zone.

Summary Serological studies were conducted on 29 leptospiral isolates obtained during an epidemiological investigation of an outbreak of human leptospirosis. The isolates were derived from urine of 2 of 6 patients, from 1 of 15 samples of surface water obtained at the locus of infection and from 15 of 106 trapped mammals as follows: 11 of 27 spiny rats (Proechimys semispinosus), 2 of 14 spiny pocket mice (Liomys adspersus), 1 of 3 opossums (Didelphis marsupialis) and 1 of 3 four-eyed opossums (Philander opossum). No leptospiras were isolated from 49 short-tailed bats (Carollia perspicillata), 6 small-eared bats (Micronycteris megalotis), and 4 long-tongued bats (Glossophaga soricina). On the basis of cross-agglutination and agglutinin adsorption tests, seven different and hitherto unreported serologic types were classified and designated as follows: serotype bravo (hyos group) isolated from man, spiny rat and spiny pocket mouse; serotype weaveri (icterohaemorrhagiae group) isolated from man and spiny rat; serotypes canalzoni (cynopteri group) isolated from spiny rat, spiny pocket mouse and four-eyed opossum; kobbe (bataviae group) isolated from spiny rat; serotype pomona, subserotype tropica, isolated from spiny rat and spiny pocket mouse; maru (hebdomadis group) isolated from spiny rat and surface water; and panama (possible new group) isolated from opossum. Evidence of mixed infections was obtained in five animals. The bacteriological findings affirmed previous serological indications that Panama is an area of multiple leptospirosis.

Sex chromatin in somatic cells of the Philander opossum quica (Temminck, 1827, Marsupialia).

In both sexes the Brazilian marsupial <i>Philander opossum quica</i> (Temminck, 1827) presents one conspicuous chromocenter in its somatic cells at interphase. The sex chromatin body in males is about half the size of the sex chromatin in females. A small, positively heteropycnotic chromosome is seen at prophase, prometaphase and metaphase in both sexes; in males it is half the size of the heteropycnotic chromosome seen in females. The sex chromosomes in this animal are the smallest in the karyotype and the Y chromosome is half the size of the X chromosome. It is concluded that in this species the sex chromatin body is formed by one condensed X chromosome in females and by the condensed Y chromosome in males.

Chromosomes of American Marsupials

Studies of the chromosomes of four American marsupials demonstrated that Caluromys derbianus and Marmosa mexicana have a diploid number of 14 chromosomes, and that Philander opossum and Didelphis marsupialis have a diploid number of 22. The karyotypes of C. derbianus and M. mexicana are similar, whereas those of P. opossum and D. marsupialis are dissimilar. If the 14-chromosome karyotype represents a reduction from a primitive number of 22, these observations suggest that the change has occurred independently in the American and Australasian forms.