Northeastern Peruvian Amazon Research Articles

Malaria Resilience in South America: Epidemiology, Vector Biology, and Immunology Insights from the Amazonian International Center of Excellence in Malaria Research Network in Peru and Brazil.

The 1990s saw the rapid reemergence of malaria in Amazonia, where it remains an important public health priority in South America. The Amazonian International Center of Excellence in Malaria Research (ICEMR) was designed to take a multidisciplinary approach toward identifying novel malaria control and elimination strategies. Based on geographically and epidemiologically distinct sites in the Northeastern Peruvian and Western Brazilian Amazon regions, synergistic projects integrate malaria epidemiology, vector biology, and immunology. The Amazonian ICEMR's overarching goal is to understand how human behavior and other sociodemographic features of human reservoirs of transmission-predominantly asymptomatically parasitemic people-interact with the major Amazonian malaria vector, Nyssorhynchus (formerly Anopheles) darlingi, and with human immune responses to maintain malaria resilience and continued endemicity in a hypoendemic setting. Here, we will review Amazonian ICEMR's achievements on the synergies among malaria epidemiology, Plasmodium-vector interactions, and immune response, and how those provide a roadmap for further research, and, most importantly, point toward how to achieve malaria control and elimination in the Americas.

Cotylophoron panamensis (Trematoda: Paramphistomidae) in Mazama americana (Artiodactyla: Cervidae) free-living in remote areas in the Peruvian Amazon.

Trematodes of the genus Cotylophoron cause mucosal lesions in pre-stomachs and in small intestine in cattle, generating losses in animal production. In the Northeastern Peruvian Amazon, the presence of Cotylophoron panamensis in the 16.7% (4/24) in free-living red brocket deers (Mazama americana) in areas distant from livestock farming suggests the red brocket is a natural wild host of C. panamensis.

Temporal patterns of visitation of birds and mammals at mineral licks in the Peruvian Amazon.

Mineral licks are key ecological resources for many species of birds and mammals in Amazonia, providing essential dietary nutrients and clays, yet little is known about which species visit and their behaviors at the mineral licks. Studying visitation and behavior at mineral licks can provide insight into the lives of otherwise secretive and elusive species. We assessed which species visited mineral licks, when they visited, and whether visits and the probability of recording groups at mineral licks were seasonal or related to the lunar cycle. We camera trapped at 52 mineral licks in the northeastern Peruvian Amazon and detected 20 mammal and 13 bird species over 6,255 camera nights. Generalized linear models assessed visitation patterns and records of groups in association with seasonality and the lunar cycle. We report nocturnal curassows (Nothocrax urumutum) visiting mineral licks for the first time. We found seasonal trends in visitation for the black agouti (Dasyprocta fuliginosa), red howler monkey (Alouatta seniculus), blue‐throated piping guan (Pipile cumanensis), red brocket deer (Mazama americana), collared peccary (Pecari tajacu), and tapir (Tapirus terrestris). Lunar trends in visitation occurred for the paca (Cuniculus paca), Brazilian porcupine (Coendou prehensilis), and red brocket deer. The probability of recording groups (>1 individual) at mineral licks was seasonal and related to lunar brightness for tapir. Overall, our results provide important context for how elusive species of birds and mammals interact with these key ecological resources on a landscape scale. The ecological importance of mineral licks for these species can provide context to seasonal changes in species occupancy and movement.

Monitoring Wildfires in the Northeastern Peruvian Amazon Using Landsat-8 and Sentinel-2 Imagery in the GEE Platform

During the latest decades, the Amazon has experienced a great loss of vegetation cover, in many cases as a direct consequence of wildfires, which became a problem at local, national, and global scales, leading to economic, social, and environmental impacts. Hence, this study is committed to developing a routine for monitoring fires in the vegetation cover relying on recent multitemporal data (2017–2019) of Landsat-8 and Sentinel-2 imagery using the cloud-based Google Earth Engine (GEE) platform. In order to assess the burnt areas (BA), spectral indices were employed, such as the Normalized Burn Ratio (NBR), Normalized Burn Ratio 2 (NBR2), and Mid-Infrared Burn Index (MIRBI). All these indices were applied for BA assessment according to appropriate thresholds. Additionally, to reduce confusion between burnt areas and other land cover classes, further indices were used, like those considering the temporal differences between pre and post-fire conditions: differential Mid-Infrared Burn Index (dMIRBI), differential Normalized Burn Ratio (dNBR), differential Normalized Burn Ratio 2 (dNBR2), and differential Near-Infrared (dNIR). The calculated BA by Sentinel-2 was larger during the three-year investigation span (16.55, 78.50, and 67.19 km2) and of greater detail (detected small areas) than the BA extracted by Landsat-8 (16.39, 6.24, and 32.93 km2). The routine for monitoring wildfires presented in this work is based on a sequence of decision rules. This enables the detection and monitoring of burnt vegetation cover and has been originally applied to an experiment in the northeastern Peruvian Amazon. The results obtained by the two satellites imagery are compared in terms of accuracy metrics and level of detail (size of BA patches). The accuracy for Landsat-8 and Sentinel-2 in 2017, 2018, and 2019 varied from 82.7–91.4% to 94.5–98.5%, respectively.

Occurrence of Dipetalonema gracile in a wild population of woolly monkey Lagothrix poeppiigii in the northeastern Peruvian Amazon.

Dipetalonema gracile (Rudolphi, 1809) (Filarioidea: Onchocercidae) is one of six species of cavities filarial parasites of Neotropical non-human primates. The present study recorded the occurrence of D. gracile, provides morphological and morphometric data and extends the geographical distribution. Adult filariae were obtained from the thoracic and abdominal cavities of 38 specimens of woolly monkey, which were used for local human consumption, in the northeastern Peruvian Amazon. Male and female filarids were processed and analysed using light and scanning electron microscopy. Details of the cephalic papillae, post-cloacal bands and papillae, vulva, phasmid position and lateral appendages are showed by scanning electron microscopy and is recorded the occurrencce of Lagothrix poeppigii monkey as a new host of this filaria in the Yavari-Mirin river basin, Peruvian Amazon.

Prevalence of Trypanosoma cruzi and Other Trypanosomatids in Frequently-Hunted Wild Mammals from the Peruvian Amazon.

To better understand the ecology of Trypanosoma cruzi in the northeastern Peruvian Amazon, we evaluated the prevalence of T. cruzi and other trypanosomatids in four orders of wild mammals hunted and consumed by inhabitants of three remote indigenous communities in the Peruvian Amazon. Of 300 wild mammals sampled, 115 (38.3%) were infected with trypanosomatids and 15 (5.0%) with T. cruzi. The prevalence of T. cruzi within each species was as follows: large rodents (Cuniculus paca, 5.5%; Dasyprocta spp., 2.6%), edentates (Dasypus novemcinctus, 4.2%), and carnivores with higher prevalence (Nasua nasua, 18.8%). The high prevalence of T. cruzi and other trypanosomatids in frequently hunted wild mammals suggests a sizeable T. cruzi sylvatic reservoir in remote Amazonian locations.

Participatory Uses of Geospatial Technologies to Leverage Multiple Knowledge Systems within Development Contexts: A Case Study from the Peruvian Amazon

Participatory approaches have proven effective at producing more inclusive and democratic forms of development, in which marginalized groups are given increased recognition. However, these approaches can also reinforce social hierarchies and political exclusion if they are not developed and implemented carefully. In particular, participatory approaches can be problematic if they too simplistically conceptualize democratic engagement as the folding of individuals into pre-existing governance structures. Utilizing a combination of feminist and postcolonial theories, this paper argues that practitioners of participatory methods must extend their thinking to the ways in which their projects foster engagement across multiple social and epistemological perspectives. Participatory geographic information systems (PGIS) methodologies are particularly effective at enabling these cross-perspectival engagements—geospatial technologies have unique capabilities for storing and visualizing knowledge from different types of knowledge systems. These different forms of knowledge can not only be visualized as multi-facetted and multi-scalar layers, but they can be directly placed in conversation with one another within the space of the map. In this way, they can be used to fundamentally transform historically unjust governance practices, rather than simply folding new subjects into unjust political structures. The authors examine these claims in the context of a case study with the Maijuna indigenous group of the northeastern Peruvian Amazon. The authors collaborated with the Maijuna to create and use a digital, spatial database to influence policy decisions about land tenure and environmental management. We show that geospatial technologies were uniquely capable of encouraging dialog and integration across indigenous, Western scientific, and state-based perspectives of the Amazon. These technologies are particularly effective at empowering traditionally marginalized perspectives within governance processes. This project therefore offers lessons about the benefits and dangers of geospatial technologies and methodologies for improving the democratic potential of development.

Infection of Laboratory-Colonized Anopheles darlingi Mosquitoes by Plasmodium vivax

Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions.

Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates in remote Peruvian Amazon.

Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the modified agglutination test (MAT). These animals were hunted by subsistence hunters along the Yavarí-Mirín River, in the northeastern Peruvian Amazon. Blood samples were collected by hunters on filter papers. For determination of T. gondii antibodies, blood was eluted from filter papers, and a titer of 1:25 was considered indicative of exposure to T. gondii. Antibodies to T. gondii were found in 26 (31.0%) peccaries (Pecari tajacu, Tayassu pecari), six (17.1%) brocket deer (Mazama americana, Mazama gouazoubira), and four (40.0%) lowland tapir (Tapirus terrestris). We also introduced a modification to the MAT protocol that allows the extraction of fluid samples from several types of laboratory-grade filter paper, thus enabling researchers to easily adapt their approaches to the materials presented to them.

Intestinal helminths in wildPeruvian red uakari monkeys(Cacajao calvus ucayalii)in the northeasternPeruvianAmazon

Parasites are important in the management of the health of primate populations. We examined 36 fecal samples from Peruvian red uakari monkeys (Cacajao calvus ucayalii) collected from wild animals in the northeastern Peruvian Amazon. Samples were positive for helminth infection. Nematodes egg: Strongyloididae, Trypanoxyuris sp., Spirurid, and a cestode egg were identified.

Functional morphology of the female genital organs in the wild ring-tailed coati (Nasua nasua) in the northeastern Peruvian Amazon

This study examines the functional morphology of genital organs of 45 wild female ring-tailed coatis (Nasua nasua (L., 1766)) in the Peruvian Amazon. The coati shows a seasonal reproductive pattern, with a concentration of births between January and March. The pregnancy rate during the reproductive season was 64.7%. Mean litter size was 4.2 fetuses and mean ovulation rate was 4.5 follicles per pregnant female, resulting in a low rate of embryo or oocyte mortality of 9.8%. The observed vaginal pattern in our study suggests that vaginal cytology could be a useful indicator for the phase of estrus. The present evaluation provides reproductive information that may be a key component in the development of management strategies for both captive and wild coati populations.

Functional Morphology of the Female Genital Organs in the Peruvian Red Uakari Monkey (Cacajao Calvus Ucayalii)

Functional morphology may provide important information that could improve methodologies for the diagnosis of the reproductive phase of females, and develop assisted breeding techniques for wildlife. This study examined features of genital organs in 19 Peruvian red uakari monkey (Cacajao calvus ucayalii) females in different reproductive stages, collected from wild animals hunted for food by rural communities in the North-eastern Peruvian Amazon, in order to provide knowledge on the reproductive physiology of this species. The observed mean ovulation rate was 1.4 follicles, and the observed maximal follicle diameter was 0.8 cm. After ovulation, the matured follicle luteinizes resulting in functional CL. In case of oocyte fertilization, the pregnancy CL grows to a maximum of 1.2 cm in diameter, and luteal volume per female decreases related to the advance of pregnancy. Pregnant females also present follicular activity until late pregnancy, but non-ovulated follicles do not undergo atretic processes and apparently transform to accessory CL, resulting in a contribution of 30% of the total luteal volume. All pregnant females delivered a single fetus at term, resulting in a rate of reproductive wastage of 20% of oocytes or embryos. The endometrium and the endometrial glands in non-pregnant females in the follicular phase show a significant increase related to the follicular growth, reaching a high proliferation in non-pregnant females in the luteal phase. The red uakari monkey showed different vaginal epithelium features in accordance with the reproductive state of the female, suggesting that vaginal cytology could be a successful methodology with which to characterize the estrous cycle of this species. The present reproductive evaluation of the Peruvian red uakari monkey provides important information that could improve the development of assisted reproductive techniques in non-human primates.

Ovarian functionality in Poeppig's woolly monkey (Lagothrix poeppigii)

This study examined ovarian features of 60 Poeppig's woolly monkey females in different reproductive stages, collected from wild animals hunted by rural communities in the North-eastern Peruvian Amazon, to provide knowledge on the reproductive physiology of this species. The observed mean ovulation rate was 1.73 follicles, reaching a maximum diameter of 1.0cm. After ovulation, the matured follicle luteinizes resulting in functional corpora lutea (CL). In case of oocyte fertilization, the “pregnancy” CL grow to a maximum of 2cm in diameter, and luteal volume decreases related to the advance of pregnancy. Pregnant females have waves of follicular activity until late pregnancy, but dominant follicles do not attain the maximum diameter of pre-ovulatory follicles. Some non-ovulated follicles of 1mm maximum diameter do not undergo atretic processes and transform to accessory CL by luteinization of the membrane granulosa, resulting in a contribution of up to 7% of the total luteal volume. All pregnant females delivered at term only 1.00 foetus, resulting in a rate of reproductive wastage of 33.3% of embryos.

Anatomicohistological Characteristics of the Tubular Genital Organs of the Female Woolly Monkey (Lagothrix poeppigii)

Functional morphology of the reproductive organs is a key component for the better understanding of reproductive patterns as well to maximize reproductive efficiency and to develop assisted breeding techniques adapted to wildlife. This study examined anatomical and histological characteristics of genital organs of 60 Poeppig's woolly monkey females in the wild in different reproductive stages, collected by rural hunters in the northeastern Peruvian Amazon. The endometrium, the endometrial glands, and the myometrium showed a significant increase in size related to the follicular growth. In nonpregnant females in the follicular phase, the endometrium, the endometrial glands, and the myometrium showed a significant increase related to the follicular growth. Nonpregnant females in the luteal phase had a thicker endometrium, a greater proliferation of endometrial glands, and a thicker myometrium, compared to females in the follicular phase. Nonpregnant females with small antral follicles presented high amounts of collagen beneath the endometrial epithelium, a sign of endometrial regeneration after menstruation that could be useful for the diagnosis of the reproductive phase in this species. A larger proportion of secreting cervical glands was observed in pregnant females compared to other females. The cervical mucous secretion occupied the lumen of the endocervical canal, assuring that no material could enter the uterus during gestation. The Poeppig's woolly monkey showed different vaginal epithelium features in accordance with the reproductive state of the female, suggesting that vaginal cytology could be a successful methodology with which to characterize the estrous cycle of wild primates. The present reproductive evaluation of Poeppig's woolly monkey provides important information that could improve the methodologies for the diagnosis of the reproductive phase of females, the assisted reproductive techniques in non-human primates, and could also give us opportunity for comparative studies and an insight into the evolution of animal reproductive biology, including humans.

Anatomicohistological Characteristics of the Tubular Genital Organs of the Female Red Brocket Deer (Mazama americana) in the Peruvian Amazon

This study examined the anatomical and histological characteristics of tubular genital organs of 51 adult female red brocket deer in the wild in different reproductive stages, collected by rural hunters in the north-eastern Peruvian Amazon. The infundibulum was characterized by a large diameter and the presence of a highly folded and ciliated epithelium, and the isthmus has a growing secretor epithelium and a thicker muscular layer. Whereas ciliated cells are more frequent in the infundibulum, epithelial secretory cells showing abundant apical secretory blebs are more frequent in the isthmus. In non-pregnant females in luteal phase, the endometrium transforms from a proliferative to a secretory type, showing a significant proliferation of endometrial uterine glands. The red brocket deer has four large circular folds in the cervix. The epithelium of the cervix is composed primarily of secretory cells. In pregnant females, the lumen of the endocervical canal is occupied by abundant mucous secretion. All pregnant females had one embryo or fetus, with a fetal sex ratio of 54.0% females to 46.0% males. This species has a cotyledonary, syndesmochorial and partially deciduate placenta, with 6-7 dome-shaped caruncles per female. The red brocket deer does not present a true cornification of the vaginal epithelial cells, and no vaginal epithelial pattern was determined according the reproductive state of the female.

Reproductive biology of the wild red brocket deer ( Mazama americana) female in the Peruvian Amazon

Knowledge of the reproductive biology is critical for the development of management strategies of the species both in captivity and in the wild, and to address conservation concerns regarding the sustainable use of a species. The present report characterizes some aspects of the reproductive biology of the wild red brocket deer inhabiting the North-eastern Peruvian Amazon region, based on the anatomical and histological examination of the female reproductive organs of 89 wild adult females in different reproductive states. The red brocket deer female presented ovarian follicular waves involving the synchronous growth of a cohort of an average 25 follicles but only one follicle generally survived and continued development, reaching maturity at 4 mm. Mean ovulation rate was 1.14 and litter size was 1 fetus. Females presented a low rate of reproductive wastage of 14.3% of embryos. Among the 89 adult females studied, 41 (46.1%) were pregnant and 48 (53.9%) were non-pregnant females. In the Northeastern Peruvian Amazon, conceptions occurred year-round in the red brocket deer but there were peaks in the rate of conception. Estimated yearly reproductive production was 0.76–0.82 young per adult female. Most pregnant females in advanced stage of pregnancy had at least one active CL, suggesting the persistence of CL throughout gestation.

Functional anatomy of the female genital organs of the wild black agouti (Dasyprocta fuliginosa) female in the Peruvian Amazon

This study examined anatomical and histological characteristics of genital organs of 38 black agouti females in the wild in different reproductive stages, collected by rural hunters in the North-eastern Peruvian Amazon. Females in the follicular phase of the estrous cycle had greater antral follicle sizes than other females, the largest antral follicle measuring 2.34mm. Antral follicles in pregnant females and females in luteal phase of the estrous cycle had an average maximum diameter smaller than 1mm. In black agouti females in follicular phase, some antral follicles are selected to continue to growth, reaching a pre-ovulatory diameter of 2mm. Mean ovulation rate was 2.5 follicles and litter size was 2.1 embryos or fetuses per pregnant female, resulting in a rate of ovum mortality of 20.8%. Many follicles from which ovulation did not occur of 1-mm maximum diameter luteinize forming accessory CL. The constituent active luteal tissues of the ovary are functional and accessory CL. Although all females had accessory CL, transformation of follicles into accessory CL occurred especially in pregnant females, resulting in a contribution from 9% to 23% of the total luteal volume as pregnancy advances. The persistence of functional CL throughout pregnancy might reflect the importance for the maintenance of gestation and may be essential for the continuous hormonal production. The duplex uterus of the agouti female is composed by two completely independent uterine horns with correspondent separate cervices opening into the vagina. In pregnant females, most remarkable observed uterine adaptations were induced by the progressive enlargement caused by the normal pregnancy evolution. The wild black agouti showed different vaginal epithelium features in accordance with the reproductive state of the female.

Why Gender in Wildlife Conservation? Notes from the Peruvian Amazon

The connections between gender and wildlife use are diverse and depend on particular economic, cultural and ethnic contexts. Challenging the common exclusion of women from wildlife conservation, this article shows the important role played by gender even in situations where women are not direct users of wildlife. Women productive and reproduc- tive unpaid work and their participation in decision-making have a direct impact in wildlife use by: 1) making male labour available to hunt or fish at times when seasonal demand for labour in agriculture peaks and 2) reducing monetary cost of family reproduction and generating alternative sources of income and supporting food production, all which might reduce pressure on wildlife. Gender also shapes different perceptions and attitudes related to wildlife, and when embedded in par- ticular ethnic views, gender also affect use of natural spaces and wildlife species. Using interdisciplinary and applied an- thropology perspectives, findings from field research conducted in the North Eastern Peruvian Amazon are used to define the role of gender in wildlife use and derive some implications for conservation interventions in this region.

Reproductive performance of the wild collared peccary (Tayassu tajacu) female in the Peruvian Amazon

Based on the gross anatomic examination of 218 adult female reproductive tracts, we characterised the reproductive biology of the wild collared peccary in the Northeastern Peruvian Amazon. Collared peccary apparently breed year round in the Northeastern Peruvian Amazon and the number of pregnant females was 92 (42.2%). Estimations suggest 1.12 births/year and a yearly reproductive production of 1.98 piglets per pregnant female. Collared peccary females presented a mean ovulation rate of 2.25 ± 0.58 CLs, a litter size of 1.77 ± 0.48 embryos or foetuses and a reproductive wastage of 0.45 ± 0.65 (21.3%) oocytes or embryos per pregnant female. A phenomenon of embryo migration was observed in 31.8% of pregnant females. This study provides reproductive information that should be taken into account in management plans.

Anatomicohistological Characteristics of the Female Genital Organs of the White‐lipped Peccary (Tayassu pecari) in the Peruvian Amazon

This study examined the anatomical and histological characteristics of the genital organs of the female white-lipped peccary in the wild in different reproductive stages, collected by rural hunters in the North-eastern Peruvian Amazon. Mean ovulation rate was 2.12 +/- 0.83 follicles and litter size was 1.78 +/- 0.41 embryos or fetuses per pregnant female, resulting in a low rate of reproductive wastage, averaging 0.33 +/- 0.66 (16.04%) oocytes or embryos per pregnancy. The ovulation rate and the anatomical performance of the uterus could limit the prolificacy of this species. Females in follicular phase showed follicular waves suggesting the synchronous growth of a cohort of follicles. Different uterine and vaginal epithelium features changed in accordance with the reproductive state of the female. Pregnant females and females in the luteal phase presented a significant proliferation of endometrial uterine glands, characterized by hyperplasia and branching of endometrial glands, and increase in the proportion of cervical epithelial cells with periodic acid-schiff (PAS)-positive granules compared with that in females in the follicular phase. Females in the follicular phase showed a more developed vaginal epithelium (in thickness and in layer composition) than females in the luteal phase and pregnant females.