Trypanosomes of small mammals in Iran

Trypanosomes in the subgenera Herpetosoma, Schizotrypanom and Megatrypanum were found in 31 small mammals representing nine species of the orders Rodentia, Insectivora and Chiroptera in Iran.     

Basal metabolic rates in mammals: taxonomic differences in the allometry of BMR and body mass

No single equation adequately describes the allometric relation between body mass and BMR for mammals. Least squares regression of log-transformed data for 248 eutherian species results in a line with a slope (-0.30) significantly different from that of Kleiber's line (-0.25). Interordinal comparisons of least squares regressions of log-transformed BMR and mass suggest that the Insectivora have a significantly steeper slope to their allometric relationship than do most other orders, while the non-insectivore orders are statistically homogeneous with respect to slope. With respect to elevation, Edentata have the lowest BMRs; Marsupialia, Primates and Chiroptera are indistinguishable from each other but above the edentates; Primates, Chiroptera, Rodentia, Lagomorpha and Carnivora form the next highest homogeneous grouping; and Artiodactyla have the highest BMRs, significantly greater than all but Lagomorpha and Carnivora. Analysis of intraordinal variation within the Rodentia suggests significant heterogeneity among families in BMR-mass allometry.     

四川省老河沟自然保护区兽类多样性红外相机调查

自然保护区的生物物种编目是区域性和全国性生物多样性研究与监测的基础,而红外相机调查技术已成为兽类物种编目的重要手段之一。老河沟自然保护区位于四川省岷山北部,位于大熊猫岷山种群分布核心地区,是2012年新建保护区。从2011-2014年,我们把保护区划分为1km×1km的方格,采用红外相机技术,对区内的兽类多样性进行了系统全面的调查。经过9,188个相机日的调查,共记录到分属7目18科的兽类。其中,有81,709份记录可以鉴定出具体物种,包括野生兽类24种,家畜1种（家狗）,分属5目14科,独立探测数总计1,766次。其余未能鉴定出具体物种的兽类记录为小型翼手目、食虫目和啮齿目动物。在24种野生兽类中,食肉目物种数最多,共4科9种;其次为偶蹄目（4科7种）与啮齿目（3科6种）。就独立探测数而言,偶蹄目兽类是记录到次数最多的类群（占总探测数43.97%）,其次是啮齿目（25.61%）和食肉目（22.44%）。被IUCN红色名录评估为“濒危EN”、“易危VU”和“近危NT”级别的物种各3种,被列为国家I级和II级重点保护野生动物的分别为4种和5种。本次调查对老河沟自然保护区内的大中型兽类进行了首次系统性编目,了解了区内兽类群落的物种组成、空间分布与相对多度,为后续的科研项目和保护管理提供了本底数据和基础信息。     

Mammals at rescue centres in the Czech Republic: Trends in intake and outcome,causes of admission,length of stay and release rate

Rescue centres in the Czech Republic care for injured, young uninjured, and otherwise physically damaged wild animals that are temporarily or permanently incapable of looking after themselves without assistance or incapable of surviving in the wild. We evaluated the numbers of mammals admitted to 37 rescue centres in the Czech Republic in a ten year period from 2011 to 2020, the causes leading to the admission of these mammals to rescue centres, their outcomes and their length of stay at rescue centres. In total, 73,499 mammals were admitted to the Czech rescue centres in the monitored period, with an increasing trend being found in the number of admissions (rSp = 0.9030, p < 0.05). The mammals admitted in the largest numbers were Chiroptera (39.36%), primarily the common pipistrelle (Pipistrellus pipistrellus), and Insectivora (35.85%), of which the largest proportion was made up of European hedgehogs (Erinaceus europaeus). Although according to the IUCN classification only 0.26% of admitted animals belonged among Endangered or Critically Endangered species, according to the Czech legislation, 47.21% of admitted mammals belonged to species in varying degrees of endangerment in this area. The most frequent reasons for admission were the admission of young (33.18%) with differences between the Orders - the highest number of admitted young of Rodentia (72.66% of all admitted Rodentia) and the lowest number of young of Chiroptera (2.74%). Of all mammals admitted to rescue centres, 45.83% were released back into the wild, 24.52% died at rescue centres, and 9.50% were euthanized. The highest release rate was achieved in Chiroptera (74.60%) especially those that suffered from malnutrition (63.09% of all admitted Chiroptera due to malnutrition). The length of stay was longest in young Artiodactyla released back to the wild (median 87 days). The data obtained from rescue centres provide an overview of the numbers and species of animals admitted and the outcome of their rehabilitation. Since almost half of mammals admitted could not be returned to the wild, it is also important to determine correctly which individuals should be treated and what is the most efficient use of resources for wildlife rehabilitation.     

A Spatially Explicit Metapopulation Model and Cattle Trade Analysis Suggests Key Determinants for the Recurrent Circulation of Rift Valley Fever Virus in a Pilot Area of Madagascar Highlands

Rift Valley fever (RVF) is a vector-borne zoonotic disease that causes high morbidity and mortality in ruminants. In 2008–2009, a RVF outbreak affected the whole Madagascar island, including the Anjozorobe district located in Madagascar highlands. An entomological survey showed the absence of Aedes among the potential RVF virus (RVFV) vector species identified in this area, and an overall low abundance of mosquitoes due to unfavorable climatic conditions during winter. No serological nor virological sign of infection was observed in wild terrestrial mammals of the area, suggesting an absence of wild RVF virus (RVFV) reservoir. However, a three years serological and virological follow-up in cattle showed a recurrent RVFV circulation. The objective of this study was to understand the key determinants of this unexpected recurrent transmission. To achieve this goal, a spatial deterministic discrete-time metapopulation model combined with cattle trade network was designed and parameterized to reproduce the local conditions using observational data collected in the area. Three scenarios that could explain the RVFV recurrent circulation in the area were analyzed: (i) RVFV overwintering thanks to a direct transmission between cattle when viraemic cows calve, vectors being absent during the winter, (ii) a low level vector-based circulation during winter thanks to a residual vector population, without direct transmission between cattle, (iii) combination of both above mentioned mechanisms. Multi-model inference methods resulted in a model incorporating both a low level RVFV winter vector-borne transmission and a direct transmission between animals when viraemic cows calve. Predictions satisfactorily reproduced field observations, 84% of cattle infections being attributed to vector-borne transmission, and 16% to direct transmission. These results appeared robust according to the sensitivity analysis. Interweaving between agricultural works in rice fields, seasonality of vector proliferation, and cattle exchange practices could be a key element for understanding RVFV circulation in this area of Madagascar highlands.     

浙江省兽类区系及地理分布

浙江省兽类区系过去有一些报道。Swinhoe(1874)曾记录宁波附近的毛冠鹿;Ping(秉志,1924)记录过定海1只幼抹香鲸;Sowerby(1933)又记述过浙江啮齿动物3种和Allen(1938-1940)浙江兽类43种;Ellerman ＆ Morrison-Scott(1951)记录浙江兽类26种;崔秀亭等(1959)报道了庆元县小型哺乳动物22种;诸葛阳(1962)报道过杭州市郊区啮齿类和食虫类12种;温业新等(1981)记述了浙江翼手类19种。最近我们查看了浙江博物馆收藏多年的兽类标本40种,其中为本省新记录的有9种。根据我们在1958-1960年、1962-1964年对本省兽类作过的调查资料,特别是1979-1981年比较系统地对杭州、加兴、金华、丽水、温州及舟山等地区的二十多个县,进行了调查。现将结果报道如下。     

A survey of intraspecific predation within the class Mammalia

The occurrence of cannibalism in mammals was studied during a general review of cannibalism (Polis, 1981). In total, there were 146 references documenting intraspecific predation in 75 species of mammals distributed between seven orders. Of these references, 138 refer to cannibalism whereas eight studies refer to intraspecific killing unaccompanied by cannibalism. Of the papers that specified the identity of both the predator and the prey, approximately 80% referred to infanticide (including cannibalism). It appears that infanticide often functions as part of a reproductive strategy. Juveniles and adults are occasional intraspecific prey for some species of Insectivora, Chiroptera, Primates, Lagomorpha, Rodentia, Carnivora, and Artio-dactyla. Cannibalism was best documented for the carnivores, rodents and primates. In general, cannibalism often occurs during normal predatory activities and is a function of low food availability, environmental stress, and a high density of conspecifics.     

Genome sizes in afrotheria, xenarthra, euarchontoglires, and laurasiatheria

Topical literature and Web site databases provide genome sizes for approximately 4,000 animal species, invertebrates and vertebrates, 330 of which are mammals. We provide the genome size for 67 mammalian species, including 51 never reported before. Knowledge of genome size facilitates sequencing projects. The data presented here encompassed 5 Metatheria (order Didelphimorphia) and 62 Eutheria: 15 Xenarthra, 24 Euarchontoglires (Rodentia), as well as 23 Laurasiatheria (22 Chiroptera and 1 species from Perissodactyla). Already available karyotypes supplement the haploid nuclear DNA contents of the respective species. Thus, we established the first comprehensive set of genome size measurements for 15 Xenarthra species (armadillos) and for 12 house-mouse species; each group was previously represented by only one species. The Xenarthra exhibited much larger genomes than the modal 3 pg DNA known for mammals. Within the genus Mus, genome sizes varied between 2.98 pg and 3.68 pg. The 22 bat species we measured support the low 2.63 pg modal value for Chiroptera. In general, the genomes of Euarchontoglires and Laurasiatheria were found being smaller than those of (Afrotheria and) Xenarthra. Interspecific variation in genome sizes is discussed with particular attention to repetitive elements, which probably promoted the adaptation of extant mammals to their environment.     

Rift Valley Fever Virus Seroprevalence in Human Rural Populations of Gabon

Background

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis caused by a phlebovirus and transmitted by Aedes mosquitoes. Humans can also be infected through direct contact with blood (aerosols) or tissues (placenta, stillborn) of infected animals. Although severe clinical cases can be observed, infection with RVF virus (RVFV) in humans is, in most cases, asymptomatic or causes a febrile illness without serious symptoms. In small ruminants RVFV mainly causes abortion and neonatal death. The distribution of RVFV has been well documented in many African countries, particularly in the north (Egypt, Sudan), east (Kenya, Tanzania, Somalia), west (Senegal, Mauritania) and south (South Africa), but also in the Indian Ocean (Madagascar, Mayotte) and the Arabian Peninsula. In contrast, the prevalence of RVFV has rarely been investigated in central African countries.

Methodology/Principal Findings

We therefore conducted a large serological survey of rural populations in Gabon, involving 4,323 individuals from 212 randomly selected villages (10.3% of all Gabonese villages). RVFV-specific IgG was found in a total of 145 individuals (3.3%) suggesting the wide circulation of Rift Valley fever virus in Gabon. The seroprevalence was significantly higher in the lakes region than in forest and savannas zones, with respective rates of 8.3%, 2.9% and 2.2%. In the lakes region, RVFV-specific IgG was significantly more prevalent in males than in females (respectively 12.8% and 3.8%) and the seroprevalence increased gradually with age in males but not in females.

Conclusions/Significance

Although RVFV was suggested to circulate at a relatively high level in Gabon, no outbreaks or even isolated cases have been documented in the country. The higher prevalence in the lakes region is likely to be driven by specific ecologic conditions favorable to certain mosquito vector species. Males may be more at risk of infection than females because they spend more time farming and hunting outside the villages, where they may be more exposed to mosquito bites and infected animals. Further investigations are needed to determine the putative sylvan cycle of RVFV, including the mosquito species and the reservoir role of wild animals in the viral maintenance cycle.     

Mosquito survey in Mauritania: Detection of Rift Valley fever virus and dengue virus and the determination of feeding patterns

In Mauritania, several mosquito-borne viruses have been reported that can cause devastating diseases in animals and humans. However, monitoring data on their occurrence and local distribution are limited. Rift Valley fever virus (RVFV) is an arthropod-borne virus that causes major outbreaks throughout the African continent and the Arabian Peninsula. The first Rift Valley fever (RVF) epidemic in Mauritania occurred in 1987 and since then the country has been affected by recurrent outbreaks of the disease. To gain information on the occurrence of RVFV as well as other mosquito-borne viruses and their vectors in Mauritania, we collected and examined 4,950 mosquitoes, belonging to four genera and 14 species. The mosquitoes were captured during 2018 in the capital Nouakchott and in southern parts of Mauritania. Evidence of RVFV was found in a mosquito pool of female Anopheles pharoensis mosquitoes collected in December on a farm near the Senegal River. At that time, 37.5% of 16 tested Montbéliarde cattle on the farm showed RVFV-specific IgM antibodies. Additionally, we detected IgM antibodies in 10.7% of 28 indigenous cattle that had been sampled on the same farm one month earlier. To obtain information on potential RVFV reservoir hosts, blood meals of captured engorged mosquitoes were analyzed. The mosquitoes mainly fed on humans (urban areas) and cattle (rural areas), but also on small ruminants, donkeys, cats, dogs and straw-colored fruit bats. Results of this study demonstrate the circulation of RVFV in Mauritania and thus the need for further research to investigate the distribution of the virus and its vectors. Furthermore, factors that may contribute to its maintenance should be analyzed more closely. In addition, two mosquito pools containing Aedes aegypti and Culex quinquefasciatus mosquitoes showed evidence of dengue virus (DENV) 2 circulation in the city of Rosso. Further studies are therefore needed to also examine DENV circulation in Mauritania.     

Ehrlichia ruminantium infection (heartwater) in wild animals

Several wild animal species have been implicated as hosts of Ehrlichia ruminantium (formerly Cowdria ruminantium), the rickettsial agent causing heartwater, a fatal disease of domestic ruminants in sub-Saharan Africa and eastern Caribbean. However, evidence for infection in most wild species is inconclusive because of inadequate diagnostic techniques. Infection has been proven only in 12 African ruminants, three non-African ruminants and two African rodents. A subclinical carrier state occurs in eight of the African ruminant species. Further studies on E. ruminantium infection in wild animal species are needed in order to determine the host range of this pathogen accurately. The host range of Ehrlichia ruminantium in wildlife is reviewed here and the role played by these species in the epidemiology and spread of heartwater is discussed.     

The helminth fauna of wild and domestic ruminants in Mongolia—a review

The helminth fauna of eight species of wild ruminants and five species of domestic ruminants sharing common grassland in Mongolia was reviewed. A total of 108 species of helminths, belonging to 40 genera, 23 families, 11 superfamilies, 6 orders and 3 classes were reported in wild and domestic ruminants in Mongolia. Several new host–helminth associations have been recorded. Twenty seven helminth species have been found in certain host species for the first time in Mongolia. These included 2 species of trematodes, 2 species of cestodes and 23 species of nematodes. Helminths that are specific for some of the examined ruminant species were determined. However, wild animals may serve as a reservoir of helminth infections for domestic animals when sharing grassland in Mongolia. The helminth fauna of the ruminants with respect to occurrence, distribution, prevalence and intensity of infection was considered for six geographic regions of Mongolia.     

Rift Valley fever virus 78kDa envelope protein attenuates virus replication in macrophage-derived cell lines and viral virulence in mice

Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus with a wide host range including ruminants and humans. RVFV outbreaks have had devastating effects on public health and the livestock industry in African countries. However, there is no approved RVFV vaccine for human use in non-endemic countries and no FDA-approved antiviral drug for RVFV treatment. The RVFV 78kDa protein (P78), which is a membrane glycoprotein, plays a role in virus dissemination in the mosquito host, but its biological role in mammalian hosts remains unknown. We generated an attenuated RVFV MP-12 strain-derived P78-High virus and a virulent ZH501 strain-derived ZH501-P78-High virus, both of which expressed a higher level of P78 and carried higher levels of P78 in the virion compared to their parental viruses. We also generated another MP-12-derived mutant virus (P78-KO virus) that does not express P78. MP-12 and P78-KO virus replicated to similar levels in fibroblast cell lines and Huh7 cells, while P78-High virus replicated better than MP-12 in Vero E6 cells, fibroblast cell lines, and Huh7 cells. Notably, P78-High virus and P78-KO virus replicated less efficiently and more efficiently, respectively, than MP-12 in macrophage cell lines. ZH501-P78-High virus also replicated poorly in macrophage cell lines. Our data further suggest that inefficient binding of P78-High virus to the cells led to inefficient virus internalization, low virus infectivity and reduced virus replication in a macrophage cell line. P78-High virus and P78-KO virus showed lower and higher virulence than MP-12, respectively, in young mice. ZH501-P78-High virus also exhibited lower virulence than ZH501 in mice. These data suggest that high levels of P78 expression attenuate RVFV virulence by preventing efficient virus replication in macrophages. Genetic alteration leading to increased P78 expression may serve as a novel strategy for the attenuation of RVFV virulence and generation of safe RVFV vaccines.     

Using host traits to predict reservoir host species of rabies virus

Wildlife are important reservoirs for many pathogens, yet the role that different species play in pathogen maintenance frequently remains unknown. This is the case for rabies, a viral disease of mammals. While Carnivora (carnivores) and Chiroptera (bats) are the canonical mammalian orders known to be responsible for the maintenance and onward transmission of rabies Lyssavirus (RABV), the role of most species within these orders remains unknown and is continually changing as a result of contemporary host shifting. We combined a trait-based analytical approach with gradient boosting machine learning models to identify physiological and ecological host features associated with being a reservoir for RABV. We then used a cooperative game theory approach to determine species-specific traits associated with known RABV reservoirs. Being a carnivore reservoir for RABV was associated with phylogenetic similarity to known RABV reservoirs, along with other traits such as having larger litters and earlier sexual maturity. For bats, location in the Americas and geographic range were the most important predictors of RABV reservoir status, along with having a large litter. Our models identified 44 carnivore and 34 bat species that are currently not recognized as RABV reservoirs, but that have trait profiles suggesting their capacity to be or become reservoirs. Further, our findings suggest that potential reservoir species among bats and carnivores occur both within and outside of areas with current RABV circulation. These results show the ability of a trait-based approach to detect potential reservoirs of infection and could inform rabies control programs and surveillance efforts by identifying the types of species and traits that facilitate RABV maintenance and transmission.     

Eutherian phylogeny from a primate perspective

Determinant formulas for up to 22 serum proteins from nineteen species in seven Eutherian orders (Chiroptera, Carnivora, Artiodactyla, Perrissodactyl, Rodentia, Proboscidea, Xenarthra) and Metatheria were derived by comparative determinant analysis from a primate (human) perspective. Plesiomorphic character states for taxon-pairs were inferred, including epitope patterns of the putative last common ancestor of Primates and non-primate Eutheria. Our approach, comparative determinant analysis, is exceptional among immunological methods in being able to define molecular character states for cladistic systematics. Average degrees of phylogenetic conservation of protein determinants varied between loci by 6.5-fold. Against the background of possible lineage-specific rates of molecular substitution, the clear immunological differentiation of the Asiatic elephant from (other) ungulates is discussed as to its phylogenetic relevance, as are the well-marked distances between guinea-pig and myomorph rodents, fissipeds and harbour seal, Mega- and Microchiroptera, or pig and ruminants. It is concluded that genetic drift influenced the rate of molecular evolution of mammalian orders to a different extent, e.g. more in the Proboscidean lineage than in the clade leading to the horse. It is concluded that the substitution rate of antigenic determinants of serum proteins correlates positively with speciation frequency in a phyletic lineage.     

Phylogeography of Rift Valley Fever virus in Africa reveals multiple introductions in Senegal and Mauritania

Rift Valley Fever (RVF) virus (Family Bunyaviridae) is an arthropod-borne RNA virus that infects primarily domestic ruminants and occasionally humans. RVF epizootics are characterized by numerous abortions and mortality among young animals. In humans, the illness is usually characterized by a mild self-limited febrile illness, which could progress to more serious complications. RVF virus is widespread and endemic in many regions of Africa. In Western Africa, several outbreaks have been reported since 1987 when the first major one occurred at the frontier of Senegal and Mauritania. Aiming to evaluate the spreading and molecular epidemiology in these countries, RVFV isolates from 1944 to 2008 obtained from 18 localities in Senegal and Mauritania and 15 other countries were investigated. Our results suggest that a more intense viral activity possibly took place during the last century compared to the recent past and that at least 5 introductions of RVFV took place in Senegal and Mauritania from distant African regions. Moreover, Barkedji in Senegal was possibly a hub associated with the three distinct entries of RVFV in West Africa.     

Faster Speciation and Reduced Extinction in the Tropics Contribute to the Mammalian Latitudinal Diversity Gradient

The increase in species richness from the poles to the tropics, referred to as the latitudinal diversity gradient, is one of the most ubiquitous biodiversity patterns in the natural world. Although understanding how rates of speciation and extinction vary with latitude is central to explaining this pattern, such analyses have been impeded by the difficulty of estimating diversification rates associated with specific geographic locations. Here, we use a powerful phylogenetic approach and a nearly complete phylogeny of mammals to estimate speciation, extinction, and dispersal rates associated with the tropical and temperate biomes. Overall, speciation rates are higher, and extinction rates lower, in the tropics than in temperate regions. The diversity of the eight most species-rich mammalian orders (covering 92% of all mammals) peaks in the tropics, except that of the Lagomorpha (hares, rabbits, and pikas) reaching a maxima in northern-temperate regions. Latitudinal patterns in diversification rates are strikingly consistent with these diversity patterns, with peaks in species richness associated with low extinction rates (Primates and Lagomorpha), high speciation rates (Diprotodontia, Artiodactyla, and Soricomorpha), or both (Chiroptera and Rodentia). Rates of range expansion were typically higher from the tropics to the temperate regions than in the other direction, supporting the “out of the tropics” hypothesis whereby species originate in the tropics and disperse into higher latitudes. Overall, these results suggest that differences in diversification rates have played a major role in shaping the modern latitudinal diversity gradient in mammals, and illustrate the usefulness of recently developed phylogenetic approaches for understanding this famous yet mysterious pattern.     

Rift Valley Fever Virus Incorporates the 78 kDa Glycoprotein into Virions Matured in Mosquito C6/36 Cells

Rift Valley fever virus (RVFV), genus Phlebovirus, family Bunyaviridae is a zoonotic arthropod-borne virus able to transition between distant host species, causing potentially severe disease in humans and ruminants. Viral proteins are encoded by three genomic segments, with the medium M segment coding for four proteins: nonstructural NSm protein, two glycoproteins Gn and Gc and large 78 kDa glycoprotein (LGp) of unknown function. Goat anti-RVFV polyclonal antibody and mouse monoclonal antibody, generated against a polypeptide unique to the LGp within the RVFV proteome, detected this protein in gradient purified RVFV ZH501 virions harvested from mosquito C6/36 cells but not in virions harvested from the mammalian Vero E6 cells. The incorporation of LGp into the mosquito cell line - matured virions was confirmed by immune-electron microscopy. The LGp was incorporated into the virions immediately during the first passage in C6/36 cells of Vero E6 derived virus. Our data indicate that LGp is a structural protein in C6/36 mosquito cell generated virions. The protein may aid the transmission from the mosquitoes to the ruminant host, with a possible role in replication of RVFV in the mosquito host. To our knowledge, this is a first report of different protein composition between virions formed in insect C6/36 versus mammalian Vero E6 cells.     

Phylogenetic position of Eulipotyphla inferred from the cDNA sequences of pepsinogens A and C

Although to date the phylogenetic position of the provisional order Eulipotyphla has been assessed by various molecular markers, it has not been conclusively clarified due to low statistical supporting values and inconsistent results. To clarify the phylogenetic position of Eulipotyphla, we cloned cDNAs for pepsinogens A and C from five mammalian species belonging to four different orders and determined their nucleotide sequences. Molecular phylogenetic analysis based on the 1st and 2nd codon positions of the protein-coding region of cDNA sequences strongly supported the close relationship between Eulipotyphla and Chiroptera. Carnivora was found to be a sister group to these two orders. The monophyly of the order Rodentia and that of the cohort Glires (Rodentia and Lagomorpha) was also shown by the present phylogenetic trees of pepsinogens.