The epidemic situation and influencing factors of plague in the foci of Meriones unguiculatus in Inner Mongolia Plateau / 中华地方病学杂志

Objective:To analyze the epidemic situation of plague among animals in the foci of Meriones unguiculatus in Inner Mongolia Plateau, and to find out key influencing factors affecting the epidemic of the plague, and to provide theoretical basis for the prediction, early warning and risk assessment of the plague. Methods:The monitoring data including gerbils density, gerbils body flea index, plague epidemic intensity, etc., as well as environmental data including temperature, precipitation and El Ni?o activity (Southern Oscillation Index, SOI) from 19 banners (counties, cities and districts) in Ulanqab Plateau area, the foci of Meriones unguiculatus in Inner Mongolia Plateau were selected. The methods of correlation analysis, structural equation model and rank correlation were used to analyze the epidemic and key influencing factors of plague among animals in the foci. Results:The plague epidemic cycle in the foci of Meriones unguiculatus in Inner Mongolia Plateau was 5 to 10 years. The correlation analysis results showed that all the factors had influence on each other. Structural equation model screened out that the main influencing factors of plague epidemic were SOI, gerbils density and temperature. SOI had a negative effect on plague epidemic intensity (-0.022) and temperature (-0.029), while gerbils density had a positive effect on plague epidemic intensity (0.014), and temperature had a negative effect on plague epidemic intensity (-0.065). In rank correlation, when the gerbils density was at a high value, the probability of high plague epidemic intensity in that year was 4/9; when SOI was at a low value, the probability was 5/9; when the temperature was at a low value, the probability was 5/9. When the plague epidemic intensity was at a high value in that year, the probability of the plague epidemic intensity being high in the following year was 5/8; when the gerbils density was at a high value in that year, the probability was 4/9; when SOI was at a low value in that year, the probability was 4/9. Conclusion:Climate and biological factors can affect prevalence of plague, and countermeasures should be taken in advance to prevent plague outbreaks when El Ni?o phenomenon, low temperature, high density of gerbils, and high previous-year prevalence of plague appear.

Neospora caninum DNA distribution in tissues of gerbils as experimental models of chronic neosporosis / [Distribuição do DNA de Neospora caninum em tecidos de gerbilos como modelos experimentais de neosporose crônica]

Neospora caninum is the main etiologic agent of neosporosis in domestic animals and its pathogenesis comprises two characteristic phases: acute and chronic. Rodents are used as experimental models to mimic acute and chronic bovine neosporosis. In this study, we inoculated a total of 27 female gerbils, with different doses of N. caninum tachyzoites aiming to induce chronic disease. DNA was extracted from different organs of each animal after spontaneous death or euthanasia. Encephalic tissues were submitted to a highly sensitive real time PCR aiming to detect chronically infected animals. All the other samples were submitted to standard PCR. A total of 11 gerbils died due to acute neosporosis, as confirmed by N. caninum DNA detection in organs. 5x103 tachyzoites/mL of N. caninum was the dosage of antigen that can induce chronic infection in gerbils. In the encephalon sections of some animals that showed clinical signs of persistent infection, we found 70% positive for the anterior encephalon section, suggesting this area as preferential for cyst formation. Therefore, we determined the doses of tachyzoites that cause acute or chronic infection and detection of positive tissues, preferably, systemic organs during acute and encephalon in chronic phases.(AU)

Neospora caninum é o principal agente etiológico da neosporose em animais domésticos, e sua patogênese compreende duas fases características: aguda e crônica. Roedores são usados como modelos experimentais para simular neosporose bovina aguda e crônica. Neste estudo, foi inoculado um total de 27 gerbilos, fêmeas, com diferentes doses de taquizoítos de N. caninum, visando induzir doença crônica. O DNA foi extraído de diferentes órgãos de cada animal após a morte espontânea ou a eutanásia. Os tecidos encefálicos foram submetidos à PCR em tempo real de alta sensibilidade para detecção de animais com infecção crônica. Todas as outras amostras foram submetidas à PCR padrão. Um total de 11 gerbilos morreu devido à neosporose aguda, como confirmado pela detecção de DNA de N. caninum nos órgãos. A dosagem de antígeno que pode induzir infecção crônica foi de 5x103 taquizoítos/mL de N. caninum. Em seções do encéfalo de alguns animais, que apresentaram sinais clínicos de infecção persistente, encontraram-se 70% de positividade para a seção do encéfalo anterior, sugerindo essa área como preferencial para a formação de cisto. Assim, foram determinadas,, em gerbilos, as dosagens de taquizoítos capazes de induzir infecção crônica ou aguda, bem como foram detectados tecidos positivos, preferencialmente, em órgãos sistêmicos, na fase aguda, e no encéfalo, na crônica.(AU)

The potential risks of animal plague in natural foci of Meriones unguiculatus in the Inner Mongolia plateau predicted by Maximum Entropy model / 中华地方病学杂志

Objective To forecast the risk distribution of inter-animal plague in Meriones unguiculatus effectively and provide scientific evidence for prevention and control of inter-animal plague,through studying the correlation between meteorological and environmental factors and inter-animal plague in Meriones unguiculatus.Methods Positive data of plague bacterial culture in 30 epidemic source areas of Merioncs unguiculatus in the Inner Mongolia plateau from 2005 to 2018,including detecting time,number of bacteria,latitude and longitude or detailed location,host type,were from the Chinese Disease Prevention and Control System Plague Prevention Management Information System and related professional institutions for plague prevention and treatment.Logistic regression was used to explore the relationship between the inter-animal plague and climate-related risk factors.The Maximum Entropy (Maxent) model was used to predict the habitat distributions of inter-animal plague,and the receiver operating characteristic (ROC) curve was used to vzlidate the model.Results There were 11 climatic factors including annual mean temperature,isothermality,temperature seasonality,mean temperature of driest quarter,mean temperature of warmest quarter,mean temperature of coldest quarter,annual precipitation,precipitation seasonality,globcover,normalized difference vegetation index and slope,were related to the outbreak of plague among Meriones unguiculatus and included in the model (OR =1.302,0.455,0.957,0.9130,4.864,0.179,0.986,1.126,0.992,0.981,0.721,P ＜ 0.01).The increase of annual mean temperature,mean temperature of warmest quarter and precipitation seasonality will increase the risk of animal plague in the plague foci of Meriones unguiculatus;the increase of isothermality,temperature seasonality,mean temperature of driest quarter,mean temperature of coldest quarter,annual precipitation,globcover,normalized difference vegetation index,and slope will reduce the risk of animal plague in the plague foci of Meriones unguiculatus.The areas under the curve (AUCs) of the Maxent model training data and test data were 0.988 and 0.985,the prediction effect of the model was better.The habitat distribution of Meriones unguiculatus plague mainly concentrated in the central and northem Ulanqabplateau,Ordos plateau,and eastern Hetao plain.Conclusions The use of Maxent model and climate data can predict the potential risks and spatial distribution of animal plague in Meriones unguiculatus;the results are accurate and reliable.

The potential risks of animal plague in natural foci of Meriones unguiculatus in the Inner Mongolia plateau predicted by Maximum Entropy model / 中华地方病学杂志

Objective@#To forecast the risk distribution of inter-animal plague in Meriones unguiculatus effectively and provide scientific evidence for prevention and control of inter-animal plague, through studying the correlation between meteorological and environmental factors and inter-animal plague in Meriones unguiculatus.@*Methods@#Positive data of plague bacterial culture in 30 epidemic source areas of Meriones unguiculatus in the Inner Mongolia plateau from 2005 to 2018, including detecting time, number of bacteria, latitude and longitude or detailed location, host type, were from the Chinese Disease Prevention and Control System Plague Prevention Management Information System and related professional institutions for plague prevention and treatment. Logistic regression was used to explore the relationship between the inter-animal plague and climate-related risk factors. The Maximum Entropy (Maxent) model was used to predict the habitat distributions of inter-animal plague, and the receiver operating characteristic (ROC) curve was used to validate the model.@*Results@#There were 11 climatic factors including annual mean temperature, isothermality, temperature seasonality, mean temperature of driest quarter, mean temperature of warmest quarter, mean temperature of coldest quarter, annual precipitation, precipitation seasonality, globcover, normalized difference vegetation index and slope, were related to the outbreak of plague among Meriones unguiculatus and included in the model (OR = 1.302, 0.455, 0.957, 0.930, 4.864, 0.179, 0.986, 1.126, 0.992, 0.981, 0.721, P < 0.01). The increase of annual mean temperature, mean temperature of warmest quarter and precipitation seasonality will increase the risk of animal plague in the plague foci of Meriones unguiculatus; the increase of isothermality, temperature seasonality, mean temperature of driest quarter, mean temperature of coldest quarter, annual precipitation, globcover, normalized difference vegetation index, and slope will reduce the risk of animal plague in the plague foci of Meriones unguiculatus. The areas under the curve (AUCs) of the Maxent model training data and test data were 0.988 and 0.985, the prediction effect of the model was better. The habitat distribution of Meriones unguiculatus plague mainly concentrated in the central and northern Ulanqab plateau, Ordos plateau, and eastern Hetao plain.@*Conclusions@#The use of Maxent model and climate data can predict the potential risks and spatial distribution of animal plague in Meriones unguiculatus; the results are accurate and reliable.

Application and evaluation of indirect hemagglutination test in the Meriones unguiculatus natural focus of Inner Mongolia / 中华地方病学杂志

Objective To analyze and evaluate the application of indirect hemagglutination test (IHA) method in the epidemic area of Meriones unguiculatus in Inner Mongolia.Methods The plague monitoring summary and epidemic analysis reports of each year in Inner Mongolia from 1996 to 2016 were collected.The serum results of the IHA method were analyzed,including the time,region and the distribution of host animals.Results From 1996 to 2016,a total of 38 096 serum samples were detected from various host animals,and 172 positive samples were detected,with a positive rate of 0.45％.In the 21 years,except 2001 and 2015,the occurrence and prevalence of plague were judged by the IHA method for the remaining 19 years.There were 10 counties detected positive sera by IHA method;the positive results were detected by IHA method in 6 kinds of host animals,including 5 rodents and 1 carnivorous,and the positive rate of Rhombomys opimus was up to 6.17％ (91/1 475),the highest titer of the seropositive host animals was as high as 1:10 240.Conclusions The IHA method is easy to operate and economical.It plays a huge role in the timely detection of the epidemic in systematic monitoring of the Meriones unguiculatus in Inner Mongolia.

Lumbosacral plexus of the mongolian gerbil(Meriones unguiculatus Milne-Edwards, 1867) / Plexo lombossacral do gerbil (Meriones unguiculatus Milne-Edwards, 1867)

The Mongolian gerbil, belonging to the Muridae family, is characterized as an economic asset in the pet market due to its easy management. Current research analyzes and describes the origin of the nerves that make up the lumbosacral plexus in the species, foregrounding comparative anatomy, especially among wild rodents. The experiment, approved by the Committee of Institutional Bioethics, involved 15 animals which had been used in other studies and were donated to the Laboratory of Applied Animal Morphophysiology of the Federal Rural University of the Semi-Arid, Mossoró, Rio Grande do Norte, Brazil. The animals were fixed in a water solution of formaldehyde 10%. After 72 hours, they were dissected, the abdominal cavity was opened and eviscerated, and the psoas minor, psoas major and the quadratus lumborum muscles were removed to inspect the nerves that form the lumbosacral plexus. Results were given in percentages and grouped in tables. The lumbosacral plexus of the Mongolian gerbil frequently derived from the ventral roots of the last thorax nerves, from the seven lumbar nerves and from the four sacral nerves (Type II ­ T12-S4). The nerves of the gerbil´s lumbosacral plexus are the iliohypogastricus, ilioinguinalis, cutaneus femoris lateralis, genitofemoralis, femoralis, obturatorius, ischiadicus, gluteus cranialis, pudendus, gluteus caudalis and rectales caudales nerves. Information on the origin of the nerves of the gerbil´s lumbosacral plexus and their description is relevant for clinical and surgical studies, and for the application of techniques or anesthetic drugs.

O esquilo da Mongólia é um roedor pertencente à família Muridae, caracterizado por seu interesse econômico no mercado pet e por ser de fácil manejo. Esta pesquisa analisa e descreve a origem dos nervos que formam o plexo lombossacral da espécie. No experimento foram utilizados 15 animais, provenientes de outros estudos aprovados pelo Comitê de Bioética Institucional, que foram doados ao Laboratório de Morfofisiologia Animal Aplicada da Universidade Federal Rural do Semi-Árido, Mossoró, Rio Grande do Norte. Os animais foram fixados em solução aquosa de formaldeído a 10%. Após 72 horas, os animais foram dissecados, realizando-se a abertura da cavidade abdominal, depois, eviscerados e em seguida, os músculos psoas maior, psoas menor e quadrado lombar foram removidos para visualização dos nervos que formam o plexo lombossacral. Os resultados foram expressos em percentagens e agrupados em tabelas. O plexo lombossacral do gerbil originou-se mais frequentemente das raízes ventrais do último nervo torácico, dos sete nervos lombares e dos quatro nervos sacrais (Tipo II ­ T12-S4). Os nervos que formaram o plexo lombossacral do gerbil foram: ílio-hipogástrico, ílioinguinal, cutâneo femoral lateral, genitofemoral, femoral, obturatório, isquiático, glúteo cranial, pudendo, glúteo caudal, e nervo retal caudal. O conhecimento sobre a origem e os nervos do plexo lombossacral no gerbil mostra-se útil para estudos clínico-cirúrgicos e aplicação de técnicas ou fármacos anestésicos.

Anthelmintic activity of Cymbopogon citratus against Haemonchus contortus / Atividade anti-helmíntica de Cymbopogon citratussobre Haemonchus contortus

Parasitic nematodes are of major economic importance in livestock. An alternative for the control of parasites is phytotherapy. This study evaluated the efficacy of Cymbopogon citratus decoction (CcD), C. citratus essential oil (CcEo) and citral against Haemonchus contortus using in vitro egg hatch test (EHT) and larval development test (LDT) and an in vivo test using a Meriones unguiculatus (gerbil) model. The effect of 800 mg/kg CcEo was evaluated in gerbils that had been artificially infected with 5,000 third-stage H. contortus larvae. The effective concentrations required to inhibit 50% (EC50) of egg hatching were 0.46, 0.14 and 0.13 mg/mL for CcD, CcEo and citral, respectively. The EC50 values in the LDT were 5.04, 1.92 and 1.37 mg/mL for CcD, CcEo and citral, respectively. H. contortus population in the group treated with C. citratus essential oil was reduced by 38.5% (P< 0.05) in comparison to the control group. These results suggest that it may be possible to use C. citratusessential oil to control of H. contortus parasite of small ruminant.

O parasitismo por nematoides tem grande importância econômica no rebanho. Uma alternativa para o controle de parasitas é a fitoterapia. Este estudo avaliou a eficácia do decocto de Cymbopogon citratus (DCc), do óleo essencial de C. citratus (OECc) e do citral contra Haemonchus contortus utilizando o teste in vitro de eclosão dos ovos (TEO) e o teste de desenvolvimento larval (TDL) e um teste in vivo com modelo Meriones unguiculatus (gerbil). O efeito de 800 mg/kg de OECc foi avaliado em gerbils infectados artificialmente com 5000 larvas de terceira fase de H. contortus. As concentrações efetivas necessárias para inibir 50% (CE50) da eclosão dos ovos foram 0,46; 0,14 e 0,13 mg/mL para DCc, OECc e citral, respectivamente. Os valores da CE50 no TDL foram de 5,04; 1,92 e 1,37 mg/mL para DCc, OECc e citral, respectivamente. No grupo tratado com óleo de C. citratus a população H. contortus foi reduzida em 38,5% (P < 0,05) em comparação com o grupo controle. Estes resultados sugerem que pode ser possível a utilização de óleo essencial de C. citratus para controle de H. contortus, parasita de pequenos ruminantes.

The epidemic situations of animal plague in the animal plague foci of Yinchuan City from 2004 to 2014 / 中华地方病学杂志

Objective To analyze the changes of gopher density and epidemic situations of animal plague in the natural plague foci of Yinchuan from 2004-2014,to sum up the epidemic regularity of the epidemic situation,and to provide a scientific basis for prevention and treatment of the plague.Methods Retrospective analysis was used in the study.The plague monitoring data were collected;the number of host animals,density of rat,media index,aetiological and serological test results were analyzed.Results From 2004 to 2014,a total of 15 664 rats in 14 species,4 families and 9 genera were captured.The dominant populations were Meriones unguiculatus and Meriones meridianus.The density of rats was 4 919 km2,the number of rats was 6 196,the density of each rat was 0.21 to 3.85/hm2,and the average density was 1.26/hm2.A total of 15 664 rats were examined,the number of positive rats was 33,and the positive rate was 0.21％ (33/15 664).Among them,gerbils were 29,accounted for 87.88％ (29/33);18 strains of Yersiniapestis were detected in dead rats,which accounted for 54.54％ (18/33).A total of 5 810 groups of 22 070 fleas were cultured,the number of positive fleas was 42,and the positive rate was 0.12％ (7/5 810).Plague fleas were 2 kinds,the same type cheopis subspecies in 6 groups of 37 fleas,Nosopsyllus laeviceps vole subspecies in 1 group of 5 fleas.The positive number of F1 antibody was 3,and the positive rate was 0.12％ (3/ 2 446).Conclusions Yinchuan City,the natural foci of plague epidemic,is in the active state.We should pay attention to the density changes of Meriones unguiculatus and strengthen the monitoring work to pick up the dead rats,and found the epidemic of animal plague as soon as possible,in order to prevent the occurrence of human plague.

Genomic library construction of different willis circle in Meriones unguiculatus / 中国比较医学杂志

Objective To find out and clone the genes that can influence different willis circle in Meriones unguiculatus, the genomic library has been made.Methods 96 clean Meriones unguiculatus were dissected according to observe the differences of willis circle, and the mixed DNA was extracted from different blood vessels.The genomic library construction has been done by using pCC1FOS vector, following by CopyControl Fosmid Lib manual.The copy numbers, recombined segment size and recombination fraction of the library were measured.Results Genomic library of different Willis circle in Meriones unguiculatus was successfully made.The capacity of the library was 1700 copies.The segment size was 36kb, and the recombination fraction was 93%.Conclusion The library was the good beginning for the following steps which were gene cloning and genescreen.

Histological observation on the urinary organs in normal Meriones Unguieulataus / 中国比较医学杂志

Objective Mongolian gerbil can make themself urine concentration for saving water and adapt to the harsh desert environment, due to their very unique moisture control system in the body.Methods Mongolian gerbil is resistant to drought on account of their special kidney. Histology of the kidney, ureter and bladder in Meriones Unguiculataus were observed by light microscopy using HE staining.Results The results showed that compared with rats and mice, the Mongolian gerbils have more developed distal tubules, and well developed inner renal medulla.Conclusions We hope that the findings of this study enrich our understanding of the histology of urinary system in Mongolian gerbils and provide support for the laboratory animalization of this animal.

Clinical and Histochemical Alterations of the Periodontal Ligament in Gerbils after Malocclusion Induced / Alteraciones Clínicas e Histoquímicas del Ligamento Periodontal en Gerbiles Después de Maloclusión Inducida

The aim of this article is to show the clinical and histochemical alterations of the first periodontal ligament, on the right side, after upper molars teeth extraction on the left side in gerbils. After two months, the periodontal ligaments were removed and processed for histochemical analysis. The data showed that TRAP reaction was able to evidence the osteoclastic activity in the hyperfunction hemimandible, right side, explaining the functional changes in the periodontal ligament after teeth extraction, and a little gingival recession and radicular exposure of teeth without function was observed at inferior molars of the left side.

El objetivo de este artículo es mostrar las alteraciones clínicas e histoquímicas del primer ligamento periodontal del lado derecho, después de la extracción del molar superior izquierdo en gerbiles {Meriones unguiculatus). Luego de dos meses, los ligamentos periodontales fueron retirados y procesados para el análisis histoquímico. Los resultados mostraron que la reacción de TRAP es capaz de evidenciar la actividad osteoclástica en la hiperfunción de la semimandíbula derecha, explicando los cambios funcionales del ligamento periodontal después de la extracción dental, siendo observada una pequeña recesión gingival y exposición radicular de los dientes sin función, en los molares inferiores izquierdos.

Loss of infectivity of Neospora caninum oocysts maintained for a prolonged time

The purpose of this study was to investigate whether sporulated Neospora caninum oocysts, which had been stored for 46 mo in a 2% sulfuric acid solution at 4 degrees C, remain morphologically viable and infective to gerbils (Meriones unguiculatus). Six gerbils were orally inoculated with doses of 400 or 1,200 oocysts. Two mo after inoculation, the animals did not show any clinical signs, had no histological lesions, and were seronegative for N. caninum at 1: 50 in an immunofluorescent antibody test. PCR using the brain from each gerbil did not reveal N. caninum specific DNA. We conclude that oocysts preserved for 46 mo are not infective, despite being morphologically intact.

Observation on Decline Phase of Maintenance of Brugia malayiMeriones unguiculatus Model / 中国寄生虫学与寄生虫病杂志

Objective To observe the degeneration of Brugia malayi in Meriones unguiculatus model. Methods Microfilaria of Brugia malayi derived from Meriones unguiculatus was used to infect Anopheles sinensis . Infective stage larvae (L 3) from mosquito vector were collected and inoculated into abdomen of Meriones unguiculatus. Successive 33 generations of the parasite in the rodent model have been observed. Results Since 1974 when the animal model was established, the parasite has lasted for 33 generations, the positive rate of Meriones unguiculatus with microfilaria gradually reduced from 80% of the 28th generation to 16% of the 32nd generation and finally to 0 at the 33rd generation. Conclusion It became difficult for the larvae of Brugia malayi to develop and/or reproduce in the animal model after multiple inoculations for generations.