Didelphis
Opossums
Marsupialia
Disease Reservoirs
Sarcocystis
Sarcocystosis
Sarcocystidae
Chagas Disease
Trypanosoma cruzi
Anal Sacs
Brazil
The program of sex chromosome pairing in meiosis is highly conserved across marsupial species: implications for sex chromosome evolution. (1/43)
Marsupials present a series of genetic and chromosomal features that are highly conserved in very distant species. One of these features is the absence of a homologous region between X and Y chromosomes. According to this genetic differentiation, sex chromosomes do not synapse during the first meiotic prophase in males, and a special structure, the dense plate, maintains sex chromosome association. In this report we present results on the process of meiotic sex chromosome pairing obtained from three different species, Thylamys elegans, Dromiciops gliroides, and Rhyncholestes raphanurus, representing the three orders of American marsupials. We have investigated the relationships between the axial structures organized along sex chromosomes and the formation of the dense plate. We found that in the three species the dense plate arises as a modification of sex chromosomal axial elements, but without the involvement of other meiotic axial structures, such as the cohesin axes. Considering the phylogenetic relationships among the marsupials studied here, our data reinforce the idea that the dense plate emerged early in marsupial evolution as an efficient mechanism to ensure the association of the nonhomologous sex chromosomes. This situation could have influenced the further evolution of sex chromosomes in marsupials. (+info)Unusually similar patterns of antibody V segment diversity in distantly related marsupials. (2/43)
A pattern of coevolution between the V gene segments of Ig H and L chains has been noted previously by several investigators. Species with restricted germline V(H) diversity tend to have limited germline V(L) diversity, whereas species with high levels of germline V(H) diversity have more diverse V(L) gene segments. Evidence for a limited pool of V(H) but diverse V(L) gene segments in a South American opossum, Monodelphis domestica, is consistent with this marsupial being an exception to the pattern. To determine whether M. domestica is unique or the norm for marsupials, the V(H) and V(L) of an Australian possum, Trichosurus vulpecula, were characterized. The Ig repertoire in T. vulpecula is also derived from a restricted V(H) pool but a diverse V(L) pool. The V(L) gene segments of T. vulpecula are highly complex and contain lineages that predate the separation of marsupials and placental mammals. Thus, neither marsupial follows a pattern of coevolution of V(H) and V(L) gene segments observed in other mammals. Rather, marsupial V(H) and V(L) complexity appears to be evolving divergently, retaining diversity in V(L) perhaps to compensate for limited V(H) diversity. There is a high degree of similarity between the V(H) and V(L) in M. domestica and T. vulpecula, with the majority of V(L) families being shared between both species. All marsupial V(H) sequences isolated so far form a common clade of closely related sequences, and in contrast to the V(L) genes, the V(H) likely underwent a major loss of diversity early in marsupial evolution. (+info)Utilization of the delay phenomenon improves blood flow and reduces collagen deposition in esophagogastric anastomoses. (3/43)
OBJECTIVE: Complications of anastomotic healing are a common source of morbidity and mortality after esophagogastrostomy. The delay phenomenon is seen when a skin flap is partially devascularized in a staged procedure prior to its definitive placement, resulting in increased blood flow at the time of grafting. This effect may be applied to esophagogastrectomy, potentially reducing anastomotic complications. SUMMARY BACKGROUND DATA: The purpose of this investigation was to apply the delay principle to the gastrointestinal tract, investigate mechanisms by which it occurs and examine the effects of delay on anastomotic healing. METHODS: Thirty-seven opossums were assigned to Sham (n = 5), Immediate (n = 14), and Delay (n = 18) groups. Each underwent laparotomy and measurement of baseline gastric fundus blood flow. The Delay and Immediate animals underwent ligation of the left, right, and short gastric vessels and subsequent measurement of gastric fundus blood flow. The Delay group underwent repeat measurement of blood flow, esophagogastrectomy, gastric tubularization, and esophagogastrostomy 28 days after vessel ligation. The Immediate group completed the procedure immediately after vessel ligation. The anastomoses in both groups were harvested 32 days after esophagogastrostomy. The Sham group underwent blood flow measurement on initial laparotomy, followed by harvesting of esophagogastric junction 60 days later. Sections taken through the anastomoses were examined with trichrome-staining and immunohistochemistry (IHC) for actin. Collagen content of the gastric submucosa 5 mm below the anastomosis was quantified, and preservation of the muscularis propria and muscularis mucosa was determined histologically. Capillary content of the esophagogastric junction was quantified using IHC for vascular endothelium in the Delay and Sham groups. RESULTS: Blood flow decreased by 73% following vessel ligation in Delay and Immediate groups. The Delay group had over 3 times the gastric blood flow of the Immediate group at the time of anastomosis at 16 (interquartile range [IQR] 11-17) versus 5, (IQR 5-6) mL/min/100 g (P = 0.000003). Two Immediate animals developed anastomotic leak and died; the Delay group had no complications. Submucosal collagen content in Sham, Delay, and Immediate groups were 57% (IQR 52-62), 65% (IQR 57-72), and 71% (IQR 60-82), respectively (P = 0.0004). The median distance of full-thickness atrophy of the muscularis propria was 0.10 mm (IQR 0-0.60 mm) in the Delay group and 0.53 mm (IQR 0.03-0.80 mm) in the Immediate group (P = 0.346). Five percent of the Delay group had atrophy of the muscularis mucosa, whereas 19% of Immediate animals had atrophy of this layer (P = 0.023). Compared with the Sham group, all Delay animals developed dilation of the right gastroepiploic artery and vein. A median of 27 (IQR 23-33) capillaries per 20x field was observed in the Sham fundus and 38 (IQR 31-46) in the Delay fundus (P = 0.037). CONCLUSIONS: The delay effect is associated with both vasodilation and angiogenesis and results in increased blood flow to the gastric fundus prior to esophagogastric anastomosis. Animals undergoing delayed operations have less anastomotic collagen deposition and ischemic injury than those undergoing immediate resection. Clinical application of the delay effect in patients undergoing esophagogastrectomy may lead to a decreased incidence of leak and stricture formation. (+info)Serologic evidence of exposure of wild mammals to flaviviruses in the central and eastern United States. (4/43)
Serosurveys were conducted to obtain flavivirus and West Nile virus (WNV) seroprevalence data from mammals. Sera from 513 small- and medium-sized mammals collected during late summer and fall 2003 from Colorado, Louisiana, New York, Ohio, and Pennsylvania were screened for flavivirus-specific antibodies. Sera samples containing antibody to flaviviruses were screened for WNV-specific antibodies by epitope-blocking enzyme-linked immunosorbent assays and confirmed with plaque reduction neutralization tests. Prevalence of WNV antibodies among study sites ranged from 0% to 42.8% among the mammal communities sampled. High prevalence rates for WNV were noted among raccoons (100%, with a very small sample size, N = 2), Virginia opossums (50.0%), fox squirrels (49.1%), and eastern gray squirrels (48.3%). The high WNV antibody prevalence noted for tree squirrels, the peri-domestic tendencies of several of these species, and their ease of observation could make these species useful sentinels for monitoring WNV activity within urban communities. (+info)Genetic characterization of Trypanosoma cruzi natural clones from the state of Paraiba, Brazil. (5/43)
Eighteen Trypanosoma cruzi stocks from the state of Paraiba, Brazil, isolated from man, wild mammals, and triatomine bugs were studied by multilocus enzyme electrophoresis and random primed amplified polymorphic DNA. Despite the low number of stocks, a notable genetic, genotypic, and phylogenetic diversity was recorded. The presence of the two main phylogenetic subdivisions, T. cruzi I and II, was recorded. The strong linkage disequilibrium observed in the population under survey suggests that T. cruzi undergoes predominant clonal evolution in this area too, although this result should be confirmed by a broader sample. The pattern of clonal variation does not suggests a recent origin by founder effect with a limited number of different genotypes. (+info)Peridomiciliary colonies of Triatoma vitticeps (Stal, 1859) (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi in rural areas of the state of Espirito Santo, Brazil. (6/43)
In Brazil, the colonization of human dwellings by triatomines occurs in areas with native vegetation of the caatinga or cerrado types. In areas of Atlantic forest such as in the Brazilian state of Espirito Santo, there are no species adapted to live in human habitations. The few autochthonous cases of Chagas disease encountered in Espirito Santo have been attributed to adult specimens of Triatoma vitticeps that invade houses from forest remnants. In recent years, the entomology unit of the Espirito Santo State Health Secretariat has recorded nymphs infected with flagellates similar to Trypanosoma cruzi in rural localities. Entomological surveys were carried out in the residences and outbuildings in which the insects were found, and serological examinations for Chagas disease performed on the inhabitants. Four colonies were found, all associated with nests of opossums (Didelphis aurita), 111 specimens of T. vitticeps, and 159 eggs being collected. All the triatomines presented flagellates in their frass. Mice inoculated with the faeces presented trypomastigotes in the circulating blood and groups of amastigotes in the cardiac muscle fibres. Serological tests performed on the inhabitants were negative for T. cruzi. Even with the intense devastation of the forest in Espirito Santo, there are no indications of change in the sylvatic habits of T. vitticeps. Colonies of this insect associated with opossum nests would indicate an expansion of the sylvatic environment into the peridomicile. (+info)Postepizootic persistence of Venezuelan equine encephalitis virus, Venezuela. (7/43)
Five years after the apparent end of the major 1995 Venezuelan equine encephalitis (VEE) epizootic/epidemic, focal outbreaks of equine encephalitis occurred in Carabobo and Barinas States of western Venezuela. Virus isolates from horses in each location were nearly identical in sequence to 1995 isolates, which suggests natural persistence of subtype IC VEE virus (VEEV) strains in a genetically stable mode. Serologic evidence indicated that additional outbreaks occurred in Barinas State in 2003. Field studies identified known Culex (Melanoconion) spp. vectors and reservoir hosts of enzootic VEEV but a dearth of typical epidemic vectors. Cattle serosurveys indicated the recent circulation of enzootic VEEV strains, and possibly of epizootic strains. Persistence of VEEV subtype IC strains and infection of horses at the end of the rainy season suggest the possibility of an alternative, cryptic transmission cycle involving survival through the dry season of infected vectors or persistently infected vertebrates. (+info)Marsupials from space: fluctuating asymmetry, geographical information systems and animal conservation. (8/43)
We report the development of a new quantitative method of assessing the effects of anthropogenic impacts on living beings; this method allows us to assess actual impacts and to travel backwards in time to assess impacts. In this method, we have crossed data on fluctuating asymmetry (FA, a measure of environmental or genetic stress), using Didelphis albiventris as a model, with geographical information systems data relating to environmental composition. Our results show that more impacted environments resulted in statistically higher levels of FA. Our method appears to be a useful and flexible conservation tool for assessing anthropogenic impacts. (+info)"Didelphis" is a genus of mammals that belongs to the family Didelphidae, which includes opossums. The name "Didelphis" itself is derived from the Greek words "di" meaning two and "delphys" meaning womb, referring to the fact that females of this genus have two separate uteri and two cervices.
The most common species in this genus is Didelphis virginiana, also known as the Virginia opossum or North American opossum. This nocturnal marsupial is native to North America and can be found in a variety of habitats ranging from forests to urban areas. It has a pointed snout, sharp teeth, and a prehensile tail that it uses for climbing and grasping objects.
Didelphis species are known for their adaptability and opportunistic feeding habits. They are omnivores that eat a wide range of foods, including fruits, insects, small mammals, birds, and reptiles. Females give birth to relatively undeveloped young that crawl into a pouch on the mother's belly and continue to develop there for several weeks before becoming independent.
I'm sorry for any confusion, but "opossums" are not a medical term or a medical condition. Opossums are actually marsupials (pouched mammals) that are native to the Americas. They are often known for their "playing dead" behavior as a defense mechanism when threatened. If you have any questions about medical terminology or health-related topics, I'd be happy to help with those!
I'm sorry for any confusion, but "Marsupialia" is not a medical term. It is a taxonomic category in biology, specifically an order that includes mammals known as marsupials. These are mammals that carry their young in a pouch after birth. Examples of marsupials include kangaroos, koalas, and opossums. If you have any medical questions or terms you would like defined, I'd be happy to help!
A disease reservoir refers to a population or group of living organisms, including humans, animals, and even plants, that can naturally carry and transmit a particular pathogen (disease-causing agent) without necessarily showing symptoms of the disease themselves. These hosts serve as a source of infection for other susceptible individuals, allowing the pathogen to persist and circulate within a community or environment.
Disease reservoirs can be further classified into:
1. **Primary (or Main) Reservoir**: This refers to the species that primarily harbors and transmits the pathogen, contributing significantly to its natural ecology and maintaining its transmission cycle. For example, mosquitoes are the primary reservoirs for many arboviruses like dengue, Zika, and chikungunya viruses.
2. **Amplifying Hosts**: These hosts can become infected with the pathogen and experience a high rate of replication, leading to an increased concentration of the pathogen in their bodies. This allows for efficient transmission to other susceptible hosts or vectors. For instance, birds are amplifying hosts for West Nile virus, as they can become viremic (have high levels of virus in their blood) and infect feeding mosquitoes that then transmit the virus to other animals and humans.
3. **Dead-end Hosts**: These hosts may become infected with the pathogen but do not contribute significantly to its transmission cycle, as they either do not develop sufficient quantities of the pathogen to transmit it or do not come into contact with potential vectors or susceptible hosts. For example, humans are dead-end hosts for many zoonotic diseases like rabies, as they cannot transmit the virus to other humans.
Understanding disease reservoirs is crucial in developing effective strategies for controlling and preventing infectious diseases, as it helps identify key species and environments that contribute to their persistence and transmission.
Sarcocystis is a genus of intracellular parasitic protozoa that belongs to the phylum Apicomplexa. These microscopic organisms are known to infect both animals and humans, causing a variety of symptoms depending on the specific species involved and the immune status of the host.
Sarcocystis spp. have a complex life cycle involving two hosts: an intermediate host, which is typically a herbivorous animal, and a definitive host, which is usually a carnivorous or omnivorous animal. The parasites form cysts, known as sarcocysts, in the muscles of the intermediate host, which are then ingested by the definitive host during feeding.
In humans, Sarcocystis spp. can cause two main types of infections: intestinal and muscular. Intestinal infection occurs when humans accidentally ingest undercooked or raw meat containing Sarcocystis cysts. The parasites then invade the human's intestinal wall, causing symptoms such as diarrhea, abdominal pain, and fever.
Muscular infection, on the other hand, is caused by the ingestion of water or food contaminated with sporocysts shed in the feces of infected definitive hosts. This type of infection is relatively rare in humans and typically causes mild symptoms such as muscle pain, weakness, and fever.
It's worth noting that while Sarcocystis spp. can cause illness in humans, they are not usually considered a significant public health concern. Proper cooking of meat and good hygiene practices can help prevent infection with these parasites.
Sarcocystosis is a parasitic infection caused by the consumption of raw or undercooked meat containing Sarcocystis cysts. It can also occur in humans through the accidental ingestion of spores that are shed in feces of infected animals. The two main species that infect humans are S. hominis and S. suihominis, with S. hominis being transmitted via cattle and S. suihominis from pigs.
The infection typically occurs without symptoms (asymptomatic) but can sometimes cause mild to severe illness, depending on the species of the parasite and the immune status of the infected person. Symptoms may include muscle pain, weakness, fever, diarrhea, nausea, vomiting, and headache.
In rare cases, sarcocystosis can affect the central nervous system (neurocysticercosis) and cause neurological symptoms such as seizures, balance problems, and difficulty speaking or swallowing. In severe cases, it can lead to respiratory failure, kidney failure, or even death.
Diagnosis of sarcocystosis is usually made by identifying the parasite in tissue samples (biopsy) or through serological tests that detect antibodies against the parasite. Treatment typically involves supportive care and anti-parasitic medications such as trimethoprim-sulfamethoxazole, pyrimethamine, or nitazoxanide. Prevention measures include cooking meat thoroughly before consumption and practicing good hygiene when handling raw meat.
Sarcocystidae is a family of parasitic protozoa that are primarily known for infecting various animals, including both domestic and wild species. These parasites have a complex life cycle involving at least two hosts: a definitive host (usually a carnivore) and an intermediate host (usually a herbivore).
The most well-known genus within Sarcocystidae is Sarcocystis, which includes several species that can infect humans. Infection with these parasites typically occurs through the consumption of undercooked or raw meat containing Sarcocystis cysts. The resulting disease in humans is called sarcocystosis and can cause a range of symptoms depending on the species involved and the location of the cysts within the body.
It's worth noting that while Sarcocystidae includes several important parasites, it is not typically considered a medical term per se. Instead, it falls more under the purview of veterinary medicine and parasitology.
Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by the protozoan *Trypanosoma cruzi*. It is primarily transmitted to humans through the feces of triatomine bugs (also called "kissing bugs"), which defecate on the skin of people while they are sleeping. The disease can also be spread through contaminated food or drink, during blood transfusions, from mother to baby during pregnancy or childbirth, and through organ transplantation.
The acute phase of Chagas disease can cause symptoms such as fever, fatigue, body aches, headache, rash, loss of appetite, diarrhea, and vomiting. However, many people do not experience any symptoms during the acute phase. After several weeks or months, most people enter the chronic phase of the disease, which can last for decades or even a lifetime. During this phase, many people do not have any symptoms, but about 20-30% of infected individuals will develop serious cardiac or digestive complications, such as heart failure, arrhythmias, or difficulty swallowing.
Chagas disease is primarily found in Latin America, where it is estimated that around 6-7 million people are infected with the parasite. However, due to increased travel and migration, cases of Chagas disease have been reported in other parts of the world, including North America, Europe, and Asia. There is no vaccine for Chagas disease, but medications are available to treat the infection during the acute phase and to manage symptoms during the chronic phase.
Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, also known as American trypanosomiasis. It's transmitted to humans and other mammals through the feces of triatomine bugs, often called "kissing bugs." The parasite can also be spread through contaminated food, drink, or from mother to baby during pregnancy or birth.
The life cycle of Trypanosoma cruzi involves two main forms: the infective metacyclic trypomastigote that is found in the bug's feces and the replicative intracellular amastigote that resides within host cells. The metacyclic trypomastigotes enter the host through mucous membranes or skin lesions, where they invade various types of cells and differentiate into amastigotes. These amastigotes multiply by binary fission and then differentiate back into trypomastigotes, which are released into the bloodstream when the host cell ruptures. The circulating trypomastigotes can then infect other cells or be taken up by another triatomine bug during a blood meal, continuing the life cycle.
Clinical manifestations of Chagas disease range from an acute phase with non-specific symptoms like fever, swelling, and fatigue to a chronic phase characterized by cardiac and gastrointestinal complications, which can develop decades after the initial infection. Early detection and treatment of Chagas disease are crucial for preventing long-term health consequences.
Anal sacs, also known as scent glands or scent sacs, are small paired sac-like structures located on either side of the anus in many mammals, including dogs and cats. These sacs produce a foul-smelling liquid that is used for marking territory and communication with other animals. In some cases, the ducts leading from the anal sacs can become blocked, causing discomfort or infection, which may require medical intervention.
I apologize, but "Brazil" is not a medical term or condition. It is the largest country in both South America and Latin America by land area and population. If you have any questions related to medical terminology or health concerns, please provide more information and I will do my best to help.
Wild animals are those species of animals that are not domesticated or tamed by humans and live in their natural habitats without regular human intervention. They can include a wide variety of species, ranging from mammals, birds, reptiles, amphibians, fish, to insects and other invertebrates.
Wild animals are adapted to survive in specific environments and have behaviors, physical traits, and social structures that enable them to find food, shelter, and mates. They can be found in various habitats such as forests, grasslands, deserts, oceans, rivers, and mountains. Some wild animals may come into contact with human populations, particularly in urban areas where their natural habitats have been destroyed or fragmented.
It is important to note that the term "wild" does not necessarily mean that an animal is aggressive or dangerous. While some wild animals can be potentially harmful to humans if provoked or threatened, many are generally peaceful and prefer to avoid contact with people. However, it is essential to respect their natural behaviors and habitats and maintain a safe distance from them to prevent any potential conflicts or harm to either party.