A functional definition to distinguish ponds from lakes and wetlands.

Ponds are often identified by their small size and shallow depths, but the lack of a universal evidence-based definition hampers science and weakens legal protection. Here, we compile existing pond definitions, compare ecosystem metrics (e.g., metabolism, nutrient concentrations, and gas fluxes) among ponds, wetlands, and lakes, and propose an evidence-based pond definition. Compiled definitions often mentioned surface area and depth, but were largely qualitative and variable. Government legislation rarely defined ponds, despite commonly using the term. Ponds, as defined in published studies, varied in origin and hydroperiod and were often distinct from lakes and wetlands in water chemistry. We also compared how ecosystem metrics related to three variables often seen in waterbody definitions: waterbody size, maximum depth, and emergent vegetation cover. Most ecosystem metrics (e.g., water chemistry, gas fluxes, and metabolism) exhibited nonlinear relationships with these variables, with average threshold changes at 3.7 ± 1.8 ha (median: 1.5 ha) in surface area, 5.8 ± 2.5 m (median: 5.2 m) in depth, and 13.4 ± 6.3% (median: 8.2%) emergent vegetation cover. We use this evidence and prior definitions to define ponds as waterbodies that are small (< 5 ha), shallow (< 5 m), with < 30% emergent vegetation and we highlight areas for further study near these boundaries. This definition will inform the science, policy, and management of globally abundant and ecologically significant pond ecosystems.

Schistosoma mansoni enhances host susceptibility to mucosal but not intravenous challenge by R5 Clade C SHIV.

BACKGROUND: The high prevalence of HIV-1/AIDS in areas endemic for schistosomiasis and other helminthic infections has led to the hypothesis that parasites increase host susceptibility to immunodeficiency virus infection. We previously showed that rhesus macaques (RM) with active schistosomiasis were significantly more likely to become systemically infected after intrarectal (i.r.) exposure to an R5-tropic clade C simian-human immunodeficiency virus (SHIV-C) than were parasite-free controls. However, we could not address whether this was due to systemic or mucosal effects. If systemic immunoactivation resulted in increased susceptibility to SHIV-C acquisition, a similarly large difference in host susceptibility would be seen after intravenous (i.v.) SHIV-C challenge. Conversely, if increased host susceptibility was due to parasite-induced immunoactivation at the mucosal level, i.v. SHIV-C challenge would not result in significant differences between parasitized and parasite-free monkeys. METHODS AND FINDINGS: We enrolled two groups of RM and infected one group with Schistosoma mansoni; the other group was left parasite-free. Both groups were challenged i.v. with decreasing doses of SHIV-C. No statistically significant differences in 50% animal infectious doses (AID(50)) or peak viremia were seen between the two groups. These data strongly contrast the earlier i.r. SHIV-C challenge (using the same virus stock) in the presence/absence of parasites, where we noted a 17-fold difference in AID(50) and one log higher peak viremia in parasitized monkeys (P<0.001 for both). The lack of significant differences after the i.v. challenge implies that the increased host susceptibility is predominantly due to parasite-mediated mucosal upregulation of virus replication and spread, rather than systemic effects. CONCLUSIONS: The major impact of schistosome-induced increased host susceptibility is at the mucosal level. Given that >90% of all new HIV-1 infections worldwide are acquired through mucosal contact, parasitic infections that inflame mucosae may play an important role in the spread of HIV-1.

Spontaneous primary squamous cell carcinoma of the lung in a rhesus macaque (Macaca mulatta).

A 3-y-old male rhesus macaque (Macaca mulatta) was noticed to be lethargic in the compound. Physical exam revealed cyanotic mucous membranes, dyspnea, bilateral harsh lung sounds, wheezing on expiration, and a firm mass possibly associated with the liver. Radiographs revealed bilateral soft tissue opacities in the thorax. Due to poor prognosis, the rhesus was euthanized, and a necropsy was performed. Both right and left lung lobes were consolidated and had multifocal white-tan masses. On cut section, the masses were firm, had areas of necrosis, hemorrhage, and often contained a tenacious exudate. Masses were identified in the liver and both kidneys. Given the morphologic features of the neoplasm, a diagnosis of squamous cell carcinoma was made. Immunohistochemistry staining for thyroid transcription factor, a nuclear transcription factor normally found in lung, thyroid, and tumors arising from either of those tissues, confirmed that the masses originated from the lung. Malignant primary lung tumors are divided into 8 main histologic subtypes: squamous cell carcinoma, small-cell carcinoma, large-cell carcinoma, adenocarcinoma, adenosquamous carcinoma, sarcomatoid carcinoma, carcinoid tumor, and salivary gland tumors. Clinical signs associated with lung tumors include, but are not limited to, dyspnea, coughing, hemoptysis, lethargy, anorexia, and weight loss. Although squamous cell carcinoma will be low on the differential list for these clinical signs, we encourage clinicians and researchers to not rule it out solely based on incidence and age of the animal.

Hormonal synchronization of the menstrual cycles of pigtail macaques to facilitate biomedical research including modeling HIV susceptibility.

BACKGROUND: Menstrual cycle synchronization of female pigtail macaques could prove an invaluable resource in studies of the reproductive tract, associated infections, and other potential research fields. We tested whether use of an oral progesterone and estradiol combination tablet could synchronize menstrual cycles following treatment discontinuation. METHODS: Daily desogestrel 0.075 mg and ethinyl estradiol 0.01 mg were administered orally to three pigtail macaques at visual onset of perineal sex swelling and were continued until all animals had received it for at least 45 days. The hormones were discontinued, and these three macaques and three controls were observed for menstruation and had blood progesterone and estrogen measured over an additional 2-month period. RESULTS: All treatment animals showed spontaneous menstrual cycle synchronization for 2 months after menstrual cycling resumed. CONCLUSION: Progesterone and estradiol combination therapy can be used in pigtail macaques to induce synchronized cycling that persists in the absence of on-going hormone treatments.

Spontaneous gastric carcinomas in sooty mangabeys (Cercocebus atys).

Sooty mangabeys (Cercocebus atys) are native to West Africa and are a natural host of SIV, which is implicated in the origin of HIV2. They have been used in studies of AIDS pathogenesis, leprosy, immune responses, reproductive biology, and behavior. Spontaneous tumors have rarely been reported in this species. However, we noted spontaneous gastric carcinomas in 8 sooty mangabeys. Four male and 4 female mangabeys had mild to severe chronic weight loss, with abdominal distention in 5 of 8 animals. At necropsy, 7 of the 8 mangabeys had prominent large ulcerated masses with severe, diffuse thickening of the pyloric wall at or near the gastric-duodenal junction, which often partially occluded the gastric lumen. Early carcinoma was an incidental finding in one mangabey. Histologically, all of the tumors were classified as adenocarcinomas. Adenocarcinomas were noncircumscribed with infiltrates of neoplastic epithelial cells, often arranged in acini. In 3 mangabeys, these infiltrates were transmural and invaded surrounding tissue locally. The adenocarcinomas were locally invasive, with metastasis to regional lymph nodes in 2 animals, but widespread metastasis was not seen. Anisocytosis, anisokaryosis, and high mitotic rates were seen in all 8 tumors. In the samples available, serology and Steiner stain did not detect Helicobacter, and immunohistochemistry failed to reveal Helicobacter or Epstein-Barr virus, 2 potential causes for human gastric carcinomas.

AIDS and optic neuritis in a rhesus monkey infected with the R5 clade C SHIV-1157ipd3N4.

A Chinese rhesus macaque infected with the pathogenic CCR5-tropic clade C simian-human immunodeficiency virus, SHIV-1157ipd3N4, had persistent viremia, depletion of CD4(+) T cells to <200 cells/µl, opportunistic infections, coagulopathy, and gradual development of bilateral blindness. MRI revealed marked thickening of both optic nerves. Histopathological evaluation showed diffuse cellular infiltration at necropsy and a focus of SHIV-infected cells. This is the first report of CNS pathology following chronic infection with an obligate R5 SHIV.

Seroprevalence of West Nile virus in nonhuman primates as related to mosquito abundance at two national primate research centers.

West Nile virus (WNV) surfaced as an emerging infectious disease in the northeastern United States in 1999, gradually spread across the continent, and is now endemic throughout North America. Outdoor-housed nonhuman primates at the Tulane National Primate Research Center (TNPRC) in Louisiana were documented with a relatively high prevalence (36%) of antibodies to West Nile virus. We examined the prevalence of antibodies to WNV in a nonhuman primate population housed in outdoor colonies at the Yerkes National Primate Research Center Field Station located near Atlanta, Georgia. We screened rhesus macaques (Macaca mulatta) and sooty mangabeys (Cercocebus atys) that were at least 3 y old by serum neutralization for antibodies to WNV and confirmed these results by hemagglutination-inhibition assay. None of the 45 rhesus monkeys had antibodies to WNV, but 3 of the 45 mangabeys (6.6%) were positive by both serum neutralization and hemagglutination-inhibition tests. The ratio of seroprevalences in the TNPRC and Yerkes primate populations was similar to the ratio of WNV incidences in people in Louisiana and Georgia from 2002 to 2004. The difference in the exposure of nonhuman primates (and possibly humans) to WNV between these 2 regions is consistent with the difference in the abundance of mammal-biting WNV-infectious mosquitoes, which was 23 times lower near Yerkes than around TNPRC in 2003 and 33 times lower in 2004.

Toxic shock due to Streptococcus pyogenes in a rhesus monkey (Macaca mulatta).

Recent years have seen a worldwide resurgence in serious infections caused by group A streptococci. This group includes Streptococcus pyogenes, one of the most common pathogens among children which causes diverse suppurative infections, such as pharyngitis, as well as nonsuppurative infections with sequelae, such as rheumatoid fever and rheumatic heart disease. S. pyogenes produces several superantigen-like erythrogenic toxins, which are believed to be associated with pyrogenicity, erythromatous skin reactions, and various immunologic and cytotoxic effects. These toxins also can cause myocardial necrosis. In addition, recently reported streptococcal infections in obstetric human patients appear to be clinically different from classic puerperal sepsis. Here, we report a case of spontaneous streptococcal infection in a pregnant female rhesus monkey (Macaca mulatta). In addition to lesions consistent with bacteremia and toxic shock, this animal had severe cardiac lesions resembling those described in humans with rheumatic heart disease. S. pyogenes was isolated from intracardiac blood, liver, placenta, and fetal tissues. This isolate also had a unique M protein gene.

Spontaneous cutaneous squamous cell carcinoma in a sooty mangabey (Cercocebus atys): a case report.

An adult sooty mangabey (Cercocebus atys) with a solid mass arising from the skin of the dorsolateral cervical area was presented to the veterinary clinical staff. Grossly, the mass was firm, elongated, ulcerated at the tip, and measured 2.7 x 2.0 x 2.3 cm. It was surgically excised and then submitted for histopathologic evaluation. On histopathology, this tumor was composed of irregular masses and cords of neoplastic squamous epithelial cells that invaded the dermis and subcutis, often undergoing keratinization and forming numerous keratin pearls. On the basis of these histologic findings, the mass was diagnosed as a squamous cell carcinoma. Additional tests, including hematologic evaluations and radiographic views of the abdominal, thoracic, and cervical areas, were normal. Sections of the tumor were analyzed by electron microscopy and showed no evidence of viral particles. To the authors' knowledge, this is the first reported case of a spontaneous cutaneous squamous cell carcinoma in a sooty mangabey.