Rabbits as reservoirs: An updated perspective of the zoonotic risk from Cryptosporidium and Giardia.

Rabbits are highly abundant in many countries and can serve as reservoirs of diseases for a diversity of pathogens including the enteric protozoan parasites, Cryptosporidium and Giardia. Both parasites shed environmentally robust environmental stages (oo/cysts) and have been responsible for numerous waterborne outbreaks of diseases. Cryptosporidium hominis and C. parvum are responsible for most infections in humans, while Giardia duodenalis assemblages A and B, cause most human cases of giardiasis. Cryptosporidium cuniculus, the dominant species infecting rabbits, is the only spceies other than C. hominis and C. parvum to have caused a waterborne outbreak of gastritis, which occurred in the United Kingdom in 2008. This review examines the prevalence of Cryptosporidium and Giardia species in rabbits to better understand the public health risks of contamination of water sources with Cryptosporidium and Giardia oo/cysts from rabbits. Despite the abundance of C. cuniculus in rabbits, reports in humans are relatively rare, with the exception of the United Kingdom and New Zealand, and reports of C. cuniculus in humans from the United Kingdom have declined substantially since the 2008 outbreak. Subtyping of C. cuniculus has supported the potential for zoonotic transmission. Relatively few studies have been conducted on Giardia, but assemblage B dominates. However, improved typing methods are required to better understand the transmission dynamics of Giardia assemblages in rabbits. Similarly, it is not well understood if pet rabbits or contaminated water are the main source of C. cuniculus infections in humans. Well-planned studies using high-resolution typing tools are required to understand the transmission dynamics better and quantify the public health risk of Cryptosporidium and Giardia from rabbits.

Urogenital development and sexual differentiation in males of the species Dasyprocta fuliginosa.

Thirteen black agouti (Dasyprocta fuliginosa) male fetuses, acquired in two areas of the Amazon Forest, were used for the purpose of morphologically describing the fetal male urogenital organs with a focus on addressing histological and macroscopic aspects. The organs of interest were dissected and photographed in situ and ex situ. Fragments were collected and subjected to routine histological processing for inclusion in paraffin, which was cut and stained by haematoxylin and eosin and Gomori's Trichrome methods and subsequently analysed in a light microscope. The results showed that the urinary tract is like that of domestic animals and is composed of smooth unilobed kidneys covered by a dense capsule of connective tissue and divided into two well-defined regions, cortical and medullary. Ureters, urethra and urinary bladder also showed macroscopic and microscopic characteristics similar to those of domestic animals. The penis of these animals has fibroelastic characteristics, with numerous keratinized structures at its apex. In the middle third of the penis, a "U" shaped penile flexure was seen; the glans penis is covered by a keratinized epidermis containing horny spicules. The presence of a penile bone in an endochondral ossification process was observed, being more developed in gestational ages greater than 76 days. The annex glands were not observed, probably because they were fetuses; only the ampulla of the ductus deferens was identified.

Abdominal aortic branches of red-rumped agouti (Dasyprocta leporina Linnaeus, 1758).

Understanding the cardiovascular system is fundamental in diagnosing pathologies and interpreting exams, such as contrast radiographs. In this context, the present study describes the collateral abdominal aorta artery branches of red-rumped agouti. Ten red-rumped agoutis, six males and four females, were assessed. The vascular system was perfused with Neoprene 450 latex coloured with a yellow pigment, dissected and analysed. Three euthanized animals were perfused with a barium sulfate solution (1 g mL-1 ) associated with latex Neoprene 450 at a 1:3 ratio to obtain contrast-enhanced radiographs. The abdominal aorta emitted the celiac artery, which in turn originated the left gastric, hepatic and splenic arteries. The second collateral branch comprised the cranial mesenteric artery, followed by the renal arteries, which emitted the adrenal arteries, with the caudal emergence of the gonadal arteries. The caudal mesenteric artery appeared in a caudal direction. The abdominal aorta divided after reaching the pelvic cavity entrance, originating the right and left common iliac arteries. Before its bifurcation, the abdominal aorta dorsocaudally emitted its last collateral branch, the median sacral artery. The collateral branches of the aorta, therefore, resemble previously described rodent patterns, with few variations.

[Overview of infectious and non-infectious diseases in French Guiana in 2022]. / Panorama des pathologies infectieuses et non infectieuses de Guyane en 2022.

Source of many myths, French Guiana represents an exceptional territory due to the richness of its biodiversity and the variety of its communities. The only European territory in Amazonia, surrounded by the Brazilian giant and the little-known Suriname, Ariane 6 rockets are launched from Kourou while 50% of the population lives below the poverty line. This paradoxical situation is a source of health problems specific to this territory, whether they be infectious diseases with unknown germs, intoxications or chronic pathologies.Some infectious diseases such as Q fever, toxoplasmosis, cryptococcosis or HIV infection are in common with temperate countries, but present specificities leading to sometimes different management and medical reasoning. In addition to these pathologies, many tropical diseases are present in an endemic and / or epidemic mode such as malaria, leishmaniasis, Chagas disease, histoplasmosis or dengue. Besides, Amazonian dermatology is extremely varied, ranging from rare but serious pathologies (Buruli ulcer, leprosy) to others which are frequent and benign such as agouti lice (mites of the family Trombiculidae) or papillonitis. Envenomations by wild fauna are not rare, and deserve an appropriate management of the incriminated taxon. Obstetrical, cardiovascular and metabolic cosmopolitan pathologies sometimes take on a particular dimension in French Guiana that must be taken into account in the management of patients. Finally, different types of intoxication are to be known by practitioners, especially due to heavy metals.European-level resources offer diagnostic and therapeutic possibilities that do not exist in the surrounding countries and regions, thus allowing the management of diseases that are not well known elsewhere.Thanks to these same European-level resources, research in Guyana occupies a key place within the Amazon region, despite a smaller population than in the surrounding countries. Thus, certain pathologies such as histoplasmosis of the immunocompromised patient, Amazonian toxoplasmosis or Q fever are hardly described in neighboring countries, probably due to under-diagnosis linked to more limited resources. French Guiana plays a leading role in the study of these diseases.The objective of this overview is to guide health care providers coming to or practicing in French Guiana in their daily practice, but also practitioners taking care of people returning from French Guiana.

Organization of Somatosensory Cortex in the South American Rodent Paca (Cuniculus paca).

INTRODUCTION: The study of non-laboratory species has been part of a broader effort to establish the basic organization of the mammalian neocortex, as these species may provide unique insights relevant to cortical organization, function, and evolution. METHODS: In the present study, the organization of three somatosensory cortical areas of the medium-sized (5-11 kg body mass) Amazonian rodent, the paca (Cuniculus paca), was determined using a combination of electrophysiological microelectrode mapping and histochemical techniques (cytochrome oxidase and NADPH diaphorase) in tangential sections. RESULTS: Electrophysiological mapping revealed a somatotopically organized primary somatosensory cortical area (S1) located in the rostral parietal cortex with a characteristic foot-medial/head-lateral contralateral body surface representation similar to that found in other species. S1 was bordered laterally by two regions housing neurons responsive to tactile stimuli, presumably the secondary somatosensory (S2) and parietal ventral (PV) cortical areas that evinced a mirror-reversal representation (relative to S1) of the contralateral body surface. The limits of the putative primary visual (V1) and primary auditory (A1) cortical areas, as well as the complete representation of the contralateral body surface in S1, were determined indirectly by the histochemical stains. Like the barrel field described in small rodents, we identified a modular arrangement located in the face representation of S1. CONCLUSIONS: The relative location, somatotopic organization, and pattern of neuropil histochemical reactivity in the three paca somatosensory cortical areas investigated are similar to those described in other mammalian species, providing additional evidence of a common plan of organization for the somatosensory cortex in the rostral parietal cortex of mammals.

Effect of Long-Term Treatment with Dexamethasone on the Liver and Kidney Histopathology, as well as Blood Biochemistry in Male Rabbits (Lepus Cuniculus).

Glucocorticoids have a wide range of pharmacological activities. Generally speaking, the steroid drugs, such as dexamethasone (DEX) can have severe side effects on the histology of different organs. In fact, glucocorticoids have been known as powerful medicines which can cure inflammation and work with the immune system to treat a wide range of health problems. Therefore, this study aimed to investigate the effects of DEX on the histological changes of the liver and kidney, as well as blood biochemical parameters. In total, 13 specific pathogen-free male Lepus Cuniculus rabbits aged 8-10 months old, with a mean weight of 1.12±0.13 kg were randomly divided into three groups. Group I (n=3) did not receive DEX, and they only received saline solution as a placebo (control). In Group II (n=5), the animals received 0.25 mg DEX/kg body weight/day for a period of 56 days, and the animals in Group III (n=5) received 0.5 mg DEX/kg body weight/day for 56 days. Blood was aspirated from the rabbit's marginal ear vein. All blood samples were centrifuged at 3000×g for 10 min to separate serum samples. Blood lipids and trace elements (zinc, copper, calcium, and iron) were measured. The microscopical analyses of the liver and kidney tissues were performed through the observation of the histological changes in the tissues. The results showed a significant (P≤0.05) decrease in the body and organ weight, as well as serum concentrations for the trace elements. On the other hand, lipid profile showed a significant increase (P≤0.05) in cholesterol, triglycerides, and low-density lipoprotein. However, a significant decrease was recorded in high-density lipoprotein in both treated groups with DEX, compared to the control group. The results of the histological evaluation showed some degrees of degeneration, necrosis, cell vacuolation, and lymphocyte infiltration in the kidney and liver tissues in the treatment groups.

Morphological, morphometric, ultrastructural, and functional evaluation of red-rumped agouti (Dasyprocta leporina) sperm during epididymal transit.

The red-rumped agouti (Dasyprocta leporina) is a hystricognath rodent with reproductive anatomical peculiarities presenting as an intra-abdominal testes-epididymis complex. This study was carried out to describe, for the first time, details related to the morphological and functional changes in sperm along the epididymal transit in agoutis. The testes-epididymal complexes were sampled from seven sexually mature agoutis. Sperm from different epididymal regions (caput, corpus, and cauda) were collected using the floating technique, and their morphology, morphometry, ultrastructure, mitochondrial activity, membrane structural integrity, and kinetic parameters were determined. The number of sperm collected (823.5 ×106 sperm) was higher in the epididymis cauda. No significant differences in normal sperm morphology among the different epididymal regions (caput, 82.42%; corpus, 86.71%; and cauda, 88.86 %) were observed. The mean head length, head width, and tail length were highest in the caput (5.15 µm, 3.44 µm, and 32.04 µm, respectively), decreasing along the epididymal transit. Ultrastructure by scanning electron microscopy (SEM) revealed agglomeration of spermatozoa from caput and corpus, thus, enabling analysis of the gametes from only the epididymal cauda with clarity. Sperm from epididymis cauda showed the greatest proportion of membrane integrity and mitochondrial activity, followed by those from corpus and caput (79.71 %, 58.9 %, 47.7 %, respectively). Significant increase in total motility, progressive motility, velocity average pathway -VAP, velocity straightline - VSL, velocity curvilinear - VCL, and rapid sperm in the caput-corpus-cauda direction were observed. These novel data contribute to the knowledge of sperm maturation in the red-rumped agouti.

Evaluation of sperm membrane functionality during epididymal transit in red-rumped agouti (Dasyprocta leporina).

We studied the sperm membrane functionality through the epididymal transit by comparing different hypoosmotic solutions and verifying possible associations among osmotic response and functional parameters of sperm in red-rumped agouti (Dasyprocta leporina). For this purpose, epididymal sperm from six sexually mature male agoutis were collected via flotation. Then, analyses of sperm parameters and hypoosmotic swelling test using different hypoosmotic solutions (0, 50 and 200 mOsm/L) in different regions of the epididymis (caput, corpus and cauda) were performed. There was an increase (p < .05) in the values for sperm concentration, the total number of sperm recovered, total and progressive motility, average path velocity, straight-line velocity, curvilinear velocity, and rapid and medium subpopulations following the caput-corpus-cauda direction. Regardless of the hypoosmotic solution, the agouti sperm membrane presented similar functional integrity in all the epididymal regions. Moreover, the highest (p < .05) osmotic responses were reached with the use of 50 mOsm/L solution in comparison to 0 and 200 mOsm/L for all the regions. Significant correlations among osmotic response and some sperm kinetic parameters were observed, especially in epididymal caput, while no correlations were found in the region of the cauda. In summary, red-rumped agouti sperm present similar membrane functionality during epididymal transit, but there are evident correlations among such functionality and sperm kinetic parameters, especially in the caput region. Moreover, we indicate the use of a 50 mOsm/L hypoosmotic solution for the analysis of this parameter through the hypoosmotic swelling test.

Opportunistic pneumonia caused by E. cuniculi in mice immunosuppressed with cyclophosphamide.

Opportunistic fungal pneumonia is a cause of concern in immunocompromised patients due to its high morbidity and mortality rates. One such opportunistic agent affecting immunocompromised patients is the microsporidia called Encephalitozoon cuniculi. This study aimed to evaluate pneumonia caused by E. cuniculi in mice treated with the immunosuppressive agent cyclophosphamide (Cy). This study also aimed to describe the immune cells associated with the microsporidial pneumonia. C57BL/6 mice were infected intravenously with E. cuniculi spores and treated with Cy (75 mg/kg/week, intraperitoneally). Thirty days post-infection, the fungal burden (qPCR), histopathological lesions, cytokine production, and the phenotype of the immune cells in the lung parenchyma were evaluated. Histologically, interstitial pneumonia with lymphocytic infiltrate was observed in the infected animals. The infiltrate mainly consisted of CD8+ and CD4+ T lymphocytes, with reduced populations of B lymphocytes and macrophages. The production of tumor necrosis factor-alpha (TNF-α) was significant in the animals of the infected groups. Also, the fungal burden was higher in the Cy-treated animals, which was confirmed by the immunohistochemical observation of spores. These results demonstrated that E. cuniculi infection of C57BL/6 mice caused lymphocytic interstitial pneumonia (characterized by a predominant lymphocytic infiltrate), which was aggravated by Cy-induced immunosuppression. Thus, these results can be used to understand the different pathological, immunological, and therapeutic aspects of lymphocytic interstitial pneumonia.

Immunocompetent rabbits infected with Cryptosporidium cuniculus as an animal model for anti-cryptosporidial drug testing.

Cryptosporidium is one of the leading causes of diarrheal disease in humans and animals, which can be severe and deadly in neonates and immunocompromised hosts. Studies on the biology of Cryptosporidium and drug discovery efforts have been hindered by a number of factors including the limited availability of animal models. Here, we report the establishment and characterization of an immunocompetent rabbit model for infection with Cryptosporidium cuniculus. By testing four known anti-cryptosporidial compounds (nitazoxanide, baicalein, curcumin and matrine), we showed that the rabbit could be used as an alternative animal model for evaluating anti-cryptosporidial drug efficacy in vivo.

Approach to the humerus and femur of the paca (Cuniculus paca, Linnaeus 1766).

The paca (Cuniculus paca, Linnaeus 1766) is a rodent species, typical of tropical regions. It is important that in addition to its commercial value as a protein source, it can be used as a scientific scope. The objective of this study was to describe the morphology of the thigh and the arm of the paca by anatomical and imaging methodology with radiography (X-ray), computed tomography (CAT scan) and magnetic resonance imaging (MRI) to determine the surgical approach of the bones of these regions. It was concluded that the imaging study through X-ray, CAT scan and MRI are reliable methods for anatomical description of wild animals that have little known about their morphology. Finally, similarly to dogs, it was determined that lateral access is the best approach to the femoral diaphysis and the medial access is the best approach to the humerus diaphysis of the paca.

Molecular eco-epidemiology of Paracoccidioides brasiliensis in road-killed mammals reveals Cerdocyon thous and Cuniculus paca as new hosts harboring this fungal pathogen.

Wild animals infected with Paracoccidioides brasiliensis represent important indicators of this fungal agent presence in the environment. The detection of this pathogen in road-killed wild animals has shown to be a key strategy for eco-epidemiological surveillance of paracoccidioidomycosis (PCM), helping to map hot spots for human infection. Molecular detection of P. brasiliensis in wild animals from PCM outbreak areas has not been performed so far. The authors investigated the presence of P. brasiliensis through nested-PCR in tissue samples obtained from road-killed animals collected nearby a human PCM outbreak spot, Rio de Janeiro state, Brazil and border areas. Eighteen species of mammals were analyzed: Dasypus novemcinctus (nine-banded armadillo, n = 6), Cerdocyon thous (crab-eating fox, n = 4), Coendou spinosus (hairy dwarf porcupine, n = 2), Lontra longicaudis (Neotropical river otter, n = 1), Procyon cancrivorus (crab-eating raccoon, n = 1), Galactis cuja (lesser grison, n = 1), Tamandua tetradactyla (collared anteater, n = 1), Cuniculus paca (paca, n = 1), and Bradypus variegatus (brown-throated three-toed sloth, n = 1). Specific P. brasiliensis sequences were detected in the liver, spleen, and lymph node samples from 4/6 (66.7%) D. novemcinctus, reinforcing the importance of these animals on Paracoccidioides ecology. Moreover, lymph nodes samples from two C. thous, as well as lung samples from the C. paca were also positive. A literature review of Paracoccidioides spp. in vertebrates in Brazil indicates C. thous and C. paca as new hosts for the fungal pathogen P. brasiliensis.

Anthelmintic usage on the performance of the Agouti (Dasyprocta leporina) reared intensively in Trinidad and Tobago, West Indies.

Anthelmintic drugs have been used strategically in livestock reared in the tropics. These drugs have been used in the treatment of endoparasitism which have resulted in an increase in the animals' performance. The agouti (Dasyprocta leporina) is a neo-tropical rodent with the potential for domestication and has been farmed intensively in Trinidad. However, the objective of this research was to investigate the effect of anthelmintic use of the growth performance of the agouti. In searching the literature, it was found that this type of study on the agouti has not been done. In this experiment fourteen weaned agoutis weighing 1kg were divided into two groups randomly. The first group (T1) was not given any anthelmintic treatment but the second group (T2) was treated with Endovet Ces® subcutaneously every three months. There were no significant differences (p > 0.05) between the two groups in the carcass weight, weight gain, dressing percentage (hot and cold), heart, lungs, skin, head and feet. However, a significant difference (p < 0.05) was seen between groups in the weight of liver and pluck. To the authors knowledge this is the first time that carcass parameters has been presented in literature. The live weight of the animals at the end of the experiment ranged from 2.4 kg to 2.6 kg and animals had a dressing percentage of 57% to 55%. The results are suggestive that the use of anthelmintic drugs in agoutis reared intensively had no significant effect on weight gain and dressing percentage.

Experimental ethology of intensively reared lowland pacas (Cuniculus paca).

The objective of this study was to evaluate and to describe the main behaviors of family groups of lowland pacas (Cuniculus paca) raised in a commercial breeding facility. We used 24 adult pacas, 16 females and 8 males, with a mean live weight of 8.2 kg and age ranging from 2 to 4 years. The animals were kept in groups of two females and one male per enclosure. Cameras were used to monitor the animals. The behaviors identified were divided into five categories (maintenance, exploratory, social interaction, reproductive, and environmental interaction). A completely randomized design in a split-split plot arrangement with three treatment factors was used: sex, period of the day, and season. The frequencies of the maintenance and environmental interaction behavioral categories were significantly higher during the day compared to the nocturnal period (P < 0.05). The duration of each behavioral category differed significantly (P < 0.05) between day and night. The frequencies of the maintenance and reproductive behavioral categories were significantly higher during the dry season compared to the rainy season (P < 0.05) and the relative duration of behaviors of the environmental interaction category was shorter during the dry season (P < 0.05). Females exhibited a significantly higher frequency of maintenance and environmental interaction than males (P < 0.05) and the duration of environmental interaction was shorter (P < 0.05) in females. The present results add to the existing knowledge on the behavior of lowland pacas raised in captivity for production of this wild species which is in the stage of domestication.

Multidrug-Resistant Salmonella enterica Isolated in Paca (Cuniculus paca) Carcasses from the Belen Market, Iquitos, Perú.

The consumption of wildlife meat is traditionally accepted in the Peruvian Amazon; however, little is known about the pathogens present in this type of food. One of the most frequently consumed species is a rodent, the paca (Cuniculus paca) or "majaz" in the Peruvian language. The objective of this study was to determine the presence of Salmonella enterica and its antimicrobial resistance profile in paca carcasses sold in the Belen Market of Iquitos-Peru. An observational, descriptive, cross-sectional study was carried out. Fresh and smoked paca carcasses (72 samples) were evaluated during the low-rain period (July 2019) in the traditional market of Iquitos, in the Amazonian Region. Meat samples were swabbed, and International Standards Organization (ISO) 6579-1: 2017 protocol was followed to Salmonella isolation. Antimicrobial susceptibility analysis was performed by the disk diffusion method. In addition, serotyping was performed by using the Kauffmann-White scheme. A total of 25 strains of S. enterica were isolated in the paca carcasses, mainly in fresh carcasses (48.6%). The serovars isolated were Agona (45.8%), Infantis (41.7%), Wangata (8.3%), and Javiana (4.2%). A considerable number of the isolated strains were multidrug resistant (40%). The highest prevalence of resistance corresponded to trimethoprim-sulfamethoxazole (64%) followed by nitrofurantoin (44%), chloramphenicol (40%), cefotaxime (40%), and nalidixic acid (40%). Ten strains isolated (40%) were identified as producers of extended spectrum beta lactamases, all in S. enterica serovar Infantis. This study describes the presence of Salmonella Infantis with multidrug resistance profiles in wildlife meat carcasses, making the consumption of this type of products a risk factor for the development of foodborne diseases in the Amazon region. Institutional Review Board: Approval Resolution of Thesis Project: N° 024-DACMVZ-DAFCVB-U.CIENTÍFICA-2019.

Evaluation of chemical restraint, isoflurane anesthesia and methadone or tramadol as preventive analgesia in spotted pacas (Cuniculus paca) subjected to laparoscopy.

OBJECTIVE: To evaluate the efficacy and cardiopulmonary effects of ketamine-midazolam for chemical restraint, isoflurane anesthesia and tramadol or methadone as preventive analgesia in spotted pacas subjected to laparoscopy. STUDY DESIGN: Prospective placebo-controlled blinded trial. ANIMALS: A total of eight captive female Cuniculus paca weighing 9.3 ± 0.9 kg. METHODS: Animals were anesthetized on three occasions with 15 day intervals. Manually restrained animals were administered midazolam (0.5 mg kg-1) and ketamine (25 mg kg-1) intramuscularly. Anesthesia was induced and maintained with isoflurane 30 minutes later. Tramadol (5 mg kg-1), methadone (0.5 mg kg-1) or saline (0.05 mL kg-1) were administered intramuscularly 15 minutes prior to laparoscopy. Heart rate (HR), respiratory rate, mean arterial pressure (MAP), peripheral oxygen saturation (SpO2), end-tidal CO2 partial pressure (Pe'CO2), end-tidal concentration of isoflurane (Fe'Iso), pH, PaO2, PaCO2, bicarbonate (HCO3-), anion gap (AG) and base excess (BE) were monitored after chemical restraint, anesthesia induction and at different laparoscopy stages. Postoperative pain was assessed by visual analog scale (VAS) for 24 hours. Variables were compared using anova or Friedman test (p < 0.05). RESULTS: Chemical restraint was effective in 92% of animals. Isoflurane anesthesia was effective; however, HR, MAP, pH and AG decreased, whereas Pe'CO2, PaO2, PaCO2, HCO3- and BE increased. MAP was stable with tramadol and methadone treatments; HR, Fe'Iso and postoperative VAS decreased. VAS was lower for a longer time with methadone treatment; SpO2 and AG decreased, whereas Pe'CO2, PaCO2 and HCO3- increased. CONCLUSIONS AND CLINICAL RELEVANCE: Ketamine-midazolam provided satisfactory restraint. Isoflurane anesthesia for laparoscopy was effective but resulted in hypotension and respiratory acidosis. Tramadol and methadone reduced isoflurane requirements, provided postoperative analgesia and caused hypercapnia, with methadone causing severe respiratory depression. Thus, the anesthetic protocol is adequate for laparoscopy in Cuniculus paca; however, methadone should be avoided.

Heterologous microsatellite primers are informative for paca (Cuniculus paca), a large rodent with economic and ecological importance.

OBJECTIVE: This study was designed to facilitate genetic studies that would allow information on population structure and genetic diversity of natural or captive stocks of paca (Cuniculus paca), a species of ecological and socioeconomic importance, by testing cross-amplification of 20 heterologous microsatellite primer pairs developed for guinea pigs (Cavia porcellus) and capybara (Hydrochoerus hydrochaeris). RESULTS: Those primers that showed the best amplification profile in blood samples were subsequently applied to scats and saliva samples, to evaluate their efficiency. Of the 13 microsatellite pairs that amplified in blood, one-third (32%) were successfully amplified in saliva and scat samples. This initial work demonstrates successful cross-amplification in paca providing a solid and promising foundation for future genetic studies with this species. The ability to quantify genetic diversity using noninvasive samples from free-ranging paca is essential to developing applied management strategies for this large neotropical rodent that is not only a prey favored by wide-ranging carnivores [e.g., jaguar (Panthera onca), puma (Puma concolor)], but is also a species targeted by illegal hunting and wildlife trade.

Fetal bone development in the lowland paca (Cuniculus paca, Rodentia, Cuniculidae) determined using ultrasonography.

Studying the timing of the main events of embryonic and fetal development may clarify the strategies adopted by species to maximize neonatal survival and the consequences of these events for their life history. This study describes bone development during the fetal phase of the lowland paca (Cuniculus paca), comparing it with other precocial or altricial species, and its relationship with the species' adaptive strategies. A total of 102 embryos/fetuses obtained over the course of 17 years through collaboration with local subsistence hunters in the Amazon were analyzed. Measurements of mineralization of the axial and appendicular skeletons were performed by ultrasonography using a 10-18-MHz linear transducer. The chronological order of occurrence of mineralization in relation to the total dorsal length (TDL) was: skull (TDL = 4.1 cm); vertebral bodies (TDL = 4.6 cm); scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula (TDL = 6.7 cm); ribs (TDL = 7.8 cm); clavicle (TDL = 8.5 cm); metacarpi/metatarsi (TDL = 11 cm); phalanges (TDL = 15 cm); tarsus (TDL = 18 cm); patella (TDL = 23 cm); and carpus (TDL = 27.2 cm). Secondary ossification centers first appeared in the femoral distal epiphysis (TDL = 16.6 cm) and tibial proximal epiphysis (TDL = 18.4 cm). Advanced fetuses (TDL > 30 cm, 97% gestational period) presented mineralization in all primary and most secondary centers. Compared to other species, paca neonates have a well-developed skeletal system at birth, which is important for their independent postnatal locomotion. Our results may contribute to the monitoring of bone development in other wild species, helping us to understand their life history, and serving as parameters for comparisons between precocial and altricial mammals.

Ovum pick-up and in vitro maturation in spotted paca (Cuniculus paca-Linnaeus, 1766).

We tested FSHp, eCG and FSHp + eCG to establish ovum pick-up (OPU) and in vitro maturation method in spotted paca. Eight healthy adult females were subjected to each of four treatments to stimulate ovarian follicular growth. All females were subjected to a hormonal protocol using a single dose of 45 mg of injectable progesterone and single intramuscular injection of 0.075 mg d-cloprostenol on day 6. Ovarian stimulation was carried out as follows: in Group TFE (FSHp and eCG), animals were treated with a single dose of 80 mg of FSHp and 200 IU of eCG intramuscularly on day 6 after the application of progesterone; in Group TF (FSHp), they were treated with a single dose of 80 mg of FSHp intramuscularly on day 6 after application of progesterone; in Group treatment eCG, they were treated with 200 IU of eCG intramuscularly on day 6 after application of progesterone; and in Group TC (saline solution), 1 ml of saline solution was administered to control does. The OPU was performed between 22 and 26 hr after gonadotropin treatments. All recovered oocytes were placed into maturation media and incubated for 24 hr. There were no differences among the mean number of observed follicles, aspirated follicles and oocytes recovered per treatment. Oocyte maturation rates did not differ among groups, except, TF and treatment eCG oocytes had greater maturation rates than TC oocytes. In this study, gonadotropin administration failed to superovulate treated does and increase oocyte retrieval efficiency. Despite the feasibility of the procedure, further studies are needed to develop and refine hormonal protocols for oocyte recovery and in vitro maturation in this species.

Age at sexual maturity, first parturition and reproductive senescence in wild lowland pacas (Cuniculus paca): Implications for harvest sustainability.

Generation length (GL) of a mammal, calculated through the age at sexual maturity, first reproduction and reproductive senescence can be used to assess the capacity of a population of a species to withstand differing amounts of hunting pressure by humans without depletion of animal numbers. Due to the lack of reproductive data for wild mammals, the GL is often difficult to determine for most species. In the present study, the GL parameters were assessed for the wild lowland paca (Cuniculus paca) from a sample of 119 female genitalia obtained during a 15-year hunter participatory program in the Amazon. The probability of female pacas being sexually active, with observable ovarian functionality or pregnancy, increased as both body and genitalia masses increased. The average body mass at puberty was 5.46 kg. Puberty was estimated to occur at 4 months of age, from which there was estimation when age at first parturition would occur 9 months after birth. Additionally, there was no indication that there was a decrease in parturition rate at more advanced ages. The estimated age of first reproduction for pacas was much less than previous estimates, most from assessments of captive animals. In addition, because there was no evidence of reproductive senescence, it is suggested that the average age of mature hunted pacas should be used to determine optimal harvesting rates of pacas by humans. The present study highlights the importance of in situ studies on reproduction of animals in their natural habitat because these will yield more accurate reproductive variable estimates than those obtained from captive animals. It is suggested that similar methods be used to accurately assess reproductive parameters of other tropical species that are hunted by humans.