By G. Mamuk. University of Tennessee, Martin.
Little is known about estrus in wild lynx xalatan 2.5ml cheap, but behavioral indicators suggest that females are only receptive for a short period xalatan 2.5 ml generic. Mating pairs only remain together for several days and females presumably mate with only one male (Ruggiero et al generic xalatan 2.5 ml on line. There is no published information about the duration or the length of estrus in captive or wild canada lynx (nowak, 1999). Furthermore, it is unclear whether this strong seasonality is mediated solely by females, or if both females and males experience physiological changes that may restrict their ability to mate throughout the year. The second characteristic is that lynx recruitment fluctuates dramatically with snowshoe hare abundance, especially in the northern part of their range (Ruggiero et al. Biologists have also speculated that females ovulate spontaneously when prey densities are high, but become induced ovulators when prey Fi g u r e 1. Se a S o n a l c h a n g e S in F ec a l a n d r o g e n metaboliteS (Fa) F o r m a l e S (), a n d F ec a l eStrogen metaboliteS (Fe) F o r 800 F e m a l e S (). Se 400 t r a z a r o n l o S v a l o r e S m e d i o S p a r a l i n c e S a d u lt o S. The reproductive physiology of lynx is therefore closely linked to the health of the snowshoe hare population, to the point that there is little to no recruitment during the low part of the cycle (Ruggiero et al. Given these constraints to canada lynx reproduction, it is unclear how climate change or anthropogenic activities may impact lynx reproduction. In order to develop effective conservation strategies and management plans for lynx, it is critical that we develop a stronger understanding of their reproductive physiology. To this end, we have initiated a research project focusing on the endocrine physiology of both captive and wild canada lynx using fecal hormone analysis. The goal of the study described here was to 1) validate assays used to quantify fecal reproductive and glucocorticoid (stress) hormone metabolites; 2) establish normative patterns of reproductive hormone expression in captive canada lynx, and 3) provide a preliminary examination of the effects of stress on reproductive physiology. Fecal samples were collected from two populations: 1) lynx in captivity and 2) lynx in holding pens. Hormone metabolite extraction and enzyme-immunoassay procedures have been previously described (Atsalis et al. Validation Fecal androgen metabolites (fA) are reliable indicators of testicular activity in lynx. First, another source of androgens could contribute to circulating levels, and thereby excreted quantities, of androgens in castrated males. Secretions of the adrenal cortex in lynx have not been studied, but could contribute to fA levels in castrated males. Second, hepatic metabolism or bacterial activity could convert other steroid molecules into androgens (Touma and Palme, 2005). Regardless of which explanation is true, the assay is reliably detecting signifcant and biologically relevant signals, and thus can be successfully employed to track androgen excretion in male canada lynx. Although we do not have data for the fall, we can speculate that fA concentrations (and thus testicular activity) begin to increase late in the fall (nov. However, captive male Eurasian lynx have a second increase in testosterone expression and testicular size in May and June (Gritz et al. This may possibly be driven by the fact that if a female Eurasian lynx loses a litter, she can begin cycling again in June or July (Gritz et al. There is limited anecdotal evidence that female canada lynx can also give birth in August, which means there would be a second period of estrous in May or June (J. However, we did not see a second increase in fecal androgens in May or June for any of the males in the study. The frequency of this second estrous in females is not known for either species, although it seems very rare for canada lynx. Given the differences in androgen expression between Eurasian and canada lynx, we can speculate that a second estrous may be somewhat more likely to occur in Eurasian lynx. Fe m a l e R e P R o d u c t I v e P h y s I o l o g y Samples were collected from nine females housed at seven institutions. Six of the females were housed with intact males and given the opportunity to breed, but only three females got pregnant. Validation The evidence that fecal estrogen metabolites (fE) refect ovarian activity is somewhat equivocal. However, we have failed to detect fE peaks associated with documented estrous behavior or known ovulations/matings. Lynx defecate about once per day, so if ovulatory estrogen spikes are very short-lived, they may be muted in the fecal sample. Therefore, it is possible that fE can be used to measure gross differences in ovarian activity, but not to monitor distinct ovarian events for this species.
In many enters the portal circulation; the larvae enter tropical countries helminth eggs have been liver and lungs prior to re-entry into the gut purchase 2.5 ml xalatan mastercard. They As adults xalatan 2.5 ml free shipping, helminths have been recovered have even been recovered from paper cur- from almost every organ including liver discount xalatan 2.5 ml on-line, rency. Sometimes infection is strictly Many species of parasitic helminths food-borne and occurs only when larvae are (nematodes, cestodes, and trematodes) live as ingested in uncooked meat. Many species of sexually mature adults in the gastrointestinal 6 Eukaryotic Parasites tract. For instance, usual to fnd school-aged children who harbor schistosome eggs are deposited against the three or four different species of helminths in inside wall of a blood vessel. These eggs are their intestine, with each species occupying a equiped with sharp spines and a battery of different portion of the gut track. Symptoms lytic enzymes that allow them to traverse the arising from heavy infection with a given hel- vessel endothelium and gut wall. Like the protozoa, the helminths occupy In the cestodes, the situation is somewhat habitats which most of us would consider different as each proglottid segment of the highly inhospitable. Adult tapeworms shed segments into bloodstream, a place where one might expect the lumen of the small intestine and they can to encounter the constant bombardment of exit the host under their own power. Other the immune systems slings and arrows of adult tapeworms produce segments that then antibody molecules and leukocytes of various disintegrate releasing their eggs into the fecal types. The molecular tions remain as such and produce no diag- basis by which this happens is not known, nostic stage. These infections present real although a number of immune evasion and problems for the clinician seeking a defnitive immunological masking mechanisms have diagnosis for their patient. Important for helminth sur- Except for the schistosomes, the trema- vival is their unique array of natural prod- todes (fukes) are all hermaphroditic. Some helminths have evolved a pore- forming protein that promotes cell elaborate adaptations in order to ensure that fusion around the anterior end of the organ- Eukaryotic Parasites 7 ism, allowing it to become embedded in epi- important mechanisms of pathogenesis are thelial tunnels. Heavy infection with some made that parasitic helminths are themselves intestinal nematodes (e. While intuitively we might sus- macologically active compounds which we pect that parasite-induced malnutrition plays may fnd useful, as well. Mechanisms of Pathogenesis Host-mediated immunopathology accounts for a large measure of the damage Helminths injure their human host both that occurs during some helminth infections. In some cases, helminths bias host mal infammation and seizures in cysticerco- immunity to produce Th-2-like responses sis are well documented. Immune regulation on the pathogens of humans are now available, so part of the parasite may also have conse- new approaches to the clinical management quences for the host regarding a wide variety of patients suffering from them are surely of viral infections. There is some evidence to to emerge from the laboratory and fnd their support the role of helminths as co-pathogens way to the bedside. Ashford identifed hookworm infection as the main cause of Puerto Rico anemia that affected nearly 60% of the rural population. He instituted successful treatment and intervention programs (construction of latrines, wearing shoes, public health education), which signifcantly reduced the death rate from anemia due to this parasite. In 1925, Ashford help to establish a school of public health in the city of Puerta de Tierra. The Protozoa varies widely from group to group, these organisms share many common features. Over 200,000 species of protozoa have A unit membrane that functions in a similar been described so far, of which more than fashion to all other eukaryotic cells binds half are represented in the fossil record. Mechanisms living species occupy every conceivable of motility take advantage of the presence of ecological niche, including marine trenches, one of a variety of structures (e. Those capa- minth species, protozoan parasites are able to ble of sexual reproduction do so within the replicate within a given host, often resulting defnitive host, resulting in the formation of in hundreds of thousands of new individuals a zygote. This single feature of their life cycle fre- tain subcellular organelles, including Golgi quently has grave consequences for the host. Collectively, these cytoplas- very same selection pressures continue to mic inclusions enable the organism to respire, play out in many parts of the world today. Many others cause that offer some protection from host immune less severe disease (e. This is due, in part, to the site genomics, and parasite proteomics have fact that some important species of parasitic also matured over the past several years. New protozoans are no longer susceptible to drugs understanding regarding the role(s) of cyto- that were once effective in limiting disease. In While the biology of parasitic protozoa addition, the details of protective host mecha- 10 The Protozoa nisms that counter the invasion process have ated in the feld of protozoan parasitology.
After mating xalatan 2.5 ml, they prednisone have been used successfully in 37-39 begin to lay eggs cheap 2.5 ml xalatan overnight delivery, completing the life cycle buy xalatan 2.5ml visa. If enough parasites are present, the Capillaria philippinensis host may suffer liver failure and die. Rarely (Chitwood, Valesquez, and Salazar this pathogen can be transmitted to humans if 1968) they accidentally ingest embryonated eggs in contaminated water or undercooked infected The genus Capillaria has four members animals. As many as ated with an outbreak of chronic gastroen- 200,000 worms have been recovered in 1 liter teritis in central Luzon. Cases have also been of bowel fuid, a consequence of autoinfec- 40 reported in Japan, Taiwan, and Korea and the tion. Diagnosis depends upon fnding eggs Adult worms resemble those of Trichi- or larvae in feces, or detecting the parasite nella spiralis in both size (Fig. Like trichinella and trichuris, the usually present in patients presenting with 40 adults have an attenuated anterior end with an abdominal pain, diarrhea, and weight loss. In this respect, its to act on larvae as well as adult worms, 41, biology mimics the autoinfectious cycle of and relapses have not yet been reported. In contrast, there is Because of the risk of autoinfection, all no evidence that patients harboring C. As infection During the epidemic in central Luzon, the progresses, the patient frst begins passing lagoons were contaminated with bed sheets 40 This embryonated, then unembryonated eggs in soiled with feces from infected patients. Avoidance parasite of waterfowl that feed on fsh and of raw or undercooked fsh and crustaceans is crustaceans, which are the intermediate hosts recommended to prevent infection. Humans become infected eating habits are, however, extremely diffcult by eating raw or undercooked infected fsh to change. In the Philippines, ingestion of jumping salad, which consists of veg- Oesophagostomum bifurcum etables and a variety of live aquatic animals (Creplin 1849) including shrimp, is thought to be a common source of this infection. The tode mostly infecting non-human primates in clinical disease consists of a rampant diarrhea Africa and Asia. In northern Togo and north- associated with malaise, anorexia, and vom- eastern Ghana, O. Patients frequently develop a protein- of these human populations, with an esti- 44-47 losing enteropathy and malabsorption of fats mated 250,000 cases. In these regions, more than several months without treatment adults 30-40 years of age have the highest 40 develop profound electrolyte imbalance. These nematodes are often called Death results from cachexia, heart failure, nodular worms because they cause nodule and secondary bacterial infections. Adult tality rate approaches 10% in some endemic worms produce about 5,000 eggs per day, areas. Some patients develop multi-nodular disease, while, in others, a Ternidens diminutus is a nematode infec- 45 single nodular mass develops. Fecal exami- and nodular lesions, but there are usually few nation is the diagnostic method of choice symptoms. Transactions of the Royal Society of Tropical Medicine and Hygiene 1983, 77 (3), 422-3. Transactions of the Royal Society of Tropical Medicine and Hygiene 2002, 96 (3), 325-6. Transactions of the Royal Society of Tropical Medicine and Hygiene 2001, 95 (3), 295-9. Transactions of the Royal Society of Tropical Medicine and Hygiene 1990, 84 (5), 720. Transactions of the Royal Society of Tropical Medicine and Hygiene 1972, 66 (2), 375-6. Aberrant Nematode Infections instead they migrate laterally in the deeper layers of the epidermis (Fig. These aberrant An intense infammatory reaction, associ- nematodes are incapable of maturing to adult ated with itching in the affected areas, devel- parasites in the human body. Secondary bacterial infections caused resulting in aberrant infections is large, this by scratching are common. It is caused by larvae of the dog and found on the lower extremities, with the but- cat hookworms Ancylostoma braziliense, tocks and anogenital region (13%) and trunk and Uncinaria stenocephala completing and upper extremities (7% each) affected less their life cycle in animal hosts, similar to the 4 frequently. These larvae are especially common on beaches in Southeast Asia, the Caribbean, and Puerto Rico, where dogs and cats are permitted to wander the beaches and freely defecate. In the human host, infection begins when the L3 larvae penetrate unbroken skin, but fail to receive the proper environmental cues. Third stage larva of Ancylostoma bra- Rather than going further in their life cycle, ziliense.