Displaced tick-parasite interactions at the host interface

Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S65-S72 ◽  
Author(s):  
P. A. Nuttall

SummaryReciprocal interactions of parasites transmitted by blood-sucking arthropod vectors have been studied primarily at the parasite–host and parasite–vector interface. The third component of this parasite triangle, the vector–host interface, has been largely ignored. Now there is growing realization that reciprocal interactions between arthropod vectors and their vertebrate hosts play a pivotal role in the survival of arthropod-borne viruses, bacteria, and protozoa. The vector–host interface is the site where the haematophagous arthropod feeds. To obtain a blood meal, the vector must overcome the host's inflammatory, haemostatic, and immune responses. This problem is greatest for ixodid ticks which may imbibe as much as 15 ml blood whilst continuously attached to their host for 10 days or more. To feed successfully, the interface between tick and host becomes a battle between the host's mechanisms for combating the tick and the tick's armoury of bioactive proteins and other chemicals which it secretes, via saliva, into the feeding lesion formed in the host's skin. Parasites entering this battlefield encounter a privileged site in their vertebrate host that has been profoundly modified by the pharmacological activities of their vector's saliva. For example, ticks suppress natural killer cells and interferons, both of which have potent antiviral activities. Not surprisingly, vector-borne parasites exploit the immunomodulated feeding site to promote their transmission and infection. Certain tick-borne viruses are so successful at this that they are transmitted from one infected tick, through the vertebrate host to a co-feeding uninfected tick, without a detectable viraemia (virus circulating in the host's blood), and with no untoward effect on the host. When such viruses do have an adverse effect on the host, they may impede their vectors' feeding. Thus important interactions between ticks and tick-borne parasites are displaced to the interface with their vertebrate host - the skin site of blood-feeding and infection.

2021 ◽  
Vol 15 (3) ◽  
pp. 54-63
Author(s):  
F. I. Vasilevich ◽  
A. M. Nikanorova ◽  
V. V. Kalmykov ◽  
A. I. Selyutina

The purpose of the research is a regression mathematical modeling of the population of small mammals, hosts of ixodid ticks in the Kaluga Region, which allows assessing the likelihood of zoonotic and vector-borne diseases.Materials and methods. For 10 years (from 2009 to 2019), a 2k multifactorial experiment was performed in the field by the method of V. V. Kalmykov (2016). The study object was mouse-like rodents that are the most common in the Kaluga Region. Rodents were counted by standard methods using techniques of V. N. Shnitnikov (1929), P. B. Yurgenson (1934) and A. N. Formozov (1937). The generally accepted steel spring traps were used. Animals were counted throughout all habitats.Results and discussion. Regression mathematical models of the mouse-like rodent population were obtained depending on the average monthly temperature, precipitation and atmospheric pressure for the year in the Non-Black Earth Zone by the example of the Kaluga Region. The specific nature of the obtained analytical model is that the greatest influence on the population of small mammals is made by the interaction effect of two factors, temperature and atmospheric pressure. Their impact is more significant than the influence of each of the three study factors separately, in particular, it is stronger than the only influence of temperature by 1.02, the only impact of precipitation by 2.58, and the only impact of atmospheric pressure by 2.72. The analytic mathematical model allows us to calculate, without significant material or time costs, populations of mouse-like rodents not only in the Kaluga Region, but also in regions with similar climate conditions.


2021 ◽  
Vol 9 (12) ◽  
pp. 2433
Author(s):  
Daniel E. Sonenshine ◽  
Philip E. Stewart

Background: Blood-feeding arthropods support a diverse array of symbiotic microbes, some of which facilitate host growth and development whereas others are detrimental to vector-borne pathogens. We found a common core constituency among the microbiota of 16 different arthropod blood-sucking disease vectors, including Bacillaceae, Rickettsiaceae, Anaplasmataceae, Sphingomonadaceae, Enterobacteriaceae, Pseudomonadaceae, Moraxellaceae and Staphylococcaceae. By comparing 21 genomes of common bacterial symbionts in blood-feeding vectors versus non-blooding insects, we found that certain enteric bacteria benefit their hosts by upregulating numerous genes coding for essential nutrients. Bacteria of blood-sucking vectors expressed significantly more genes (p < 0.001) coding for these essential nutrients than those of non-blooding insects. Moreover, compared to endosymbionts, the genomes of enteric bacteria also contained significantly more genes (p < 0.001) that code for the synthesis of essential amino acids and proteins that detoxify reactive oxygen species. In contrast, microbes in non-blood-feeding insects expressed few gene families coding for these nutrient categories. We also discuss specific midgut bacteria essential for the normal development of pathogens (e.g., Leishmania) versus others that were detrimental (e.g., bacterial toxins in mosquitoes lethal to Plasmodium spp.).


Author(s):  
Yuliya Aleksandrovna Panferova ◽  
Regina Ravilevna Baimova ◽  
Elena Aleksandrovna Syuzyumova ◽  
Valeriya Igorevna Lomonosova ◽  
Gelena Anatolievna Lunina ◽  
...  

The prevalence of Q fever agent, Coxiella burnetii in blood-sucking ixodid ticks in the forest zones of St-Petersburg was investigated. Molecular markers of pathogen were determined in approximately 5 % of vectors, which could suggest of infection foci subsistence close to megalopolis. Data on Coxiella infection rates of arthropod vectors across the North Eurasia were analyzed.


Author(s):  
Phineas T. Hamilton ◽  
Elodie Maluenda ◽  
Anouk Sarr ◽  
Alessandro Belli ◽  
Georgia Hurry ◽  
...  

The microbiome of blood-sucking arthropods can shape their competence to acquire and maintain infections with vector-borne pathogens. We used a controlled study to investigate the interactions between Borrelia afzelii , which causes Lyme disease in Europe, and the bacterial microbiome of Ixodes ricinus , its primary tick vector. We applied a surface sterilization treatment to I. ricinus eggs to produce dysbiosed tick larvae that had a much lower bacterial abundance and a changed bacterial microbiome compared to the control larvae. Dysbiosed and control larvae were fed on B. afzelii -infected mice and uninfected control mice and the engorged larvae were left to molt into nymphs, which were tested for B. afzelii infection and their bacterial microbiome by 16S rRNA amplicon sequencing. Surprisingly, larval dysbiosis had no effect on the vector competence of I. ricinus for B. afzelii , as the nymphal infection prevalence and the nymphal spirochete load were the same between the dysbiosed group and the control group. The strong effect of egg surface sterilization on the tick bacterial microbiome largely disappeared once the larvae molted into nymphs. The most important determinant of the bacterial microbiome of I. ricinus nymphs was the B. afzelii infection status of the mouse on which the nymphs had fed as larvae. Nymphs that had taken their larval blood meal from an infected mouse had a less abundant but more diverse bacterial microbiome compared to control nymphs. Our study demonstrates that vector-borne infections in the vertebrate host shape the microbiome of the arthropod vector. IMPORTANCE Many blood-sucking arthropods transmit pathogens that cause infectious disease. For example, Ixodes ricinus ticks transmit the bacterium Borrelia afzelii , which causes Lyme disease in humans. Ticks also have a microbiome, which can influence their ability to acquire and transmit tick-borne pathogens like B. afzelii . We sterilized I. ricinus eggs with bleach, and the tick larvae that hatched from these eggs had a dramatically reduced and changed bacterial microbiome compared to control larvae. These larvae were fed on B. afzelii -infected mice and the resultant nymphs were tested for B. afzelii and their bacterial microbiome. We found that our manipulation of the bacterial microbiome had no effect on the ability of the tick larvae to acquire and maintain populations of B. afzelii . In contrast, we found that B. afzelii infection had dramatic effects on the bacterial microbiome of I. ricinus nymphs. Our study demonstrates that infections in the vertebrate host can shape the tick microbiome.


Pathogens ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 2
Author(s):  
Erik Neff ◽  
Christopher C. Evans ◽  
Pablo D. Jimenez Castro ◽  
Ray M. Kaplan ◽  
Guha Dharmarajan

Parasite drug resistance presents a major obstacle to controlling and eliminating vector-borne diseases affecting humans and animals. While vector-borne disease dynamics are affected by factors related to parasite, vertebrate host and vector, research on drug resistance in filarial parasites has primarily focused on the parasite and vertebrate host, rather than the mosquito. However, we expect that the physiological costs associated with drug resistance would reduce the fitness of drug-resistant vs. drug-susceptible parasites in the mosquito wherein parasites are not exposed to drugs. Here we test this hypothesis using four isolates of the dog heartworm (Dirofilaria immitis)—two drug susceptible and two drug resistant—and two vectors—the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Ae. albopictus)—as our model system. Our data indicated that while vector species had a significant effect on vectorial capacity, there was no significant difference in the vectorial capacity of mosquitoes infected with drug-resistant vs. drug-susceptible parasites. Consequently, contrary to expectations, our data indicate that drug resistance in D. immitis does not appear to reduce the transmission efficiency of these parasites, and thus the spread of drug-resistant parasites in the vertebrate population is unlikely to be mitigated by reduced fitness in the mosquito vector.


2021 ◽  
Vol 42 (1) ◽  
pp. 41-48
Author(s):  
A.O. Omonona ◽  
S.A. Abioye ◽  
P.O. Odeniran ◽  
I.O. Ademola

Dipteran flies play significant role in disease transmission to human, domestic and wild animals. The distribution and diversity of dipteran flies of medical and veterinary importance in Old Oyo national park and its significant importance were assessed in relation to altitude and ecology. Twelve Nzi traps were set at 50 m equidistance to capture dipteran flies between February and August 2019. A total of 1529 dipteran flies belonging to five families were captured. More dipteran flies (64.9%) were trapped during the dry season than wet season (35.1%) (X2 = 270.8; P < 0.0001; OR = 3.41). Of the total flies caught, 289 representing 18.9% were identified as haematophagus flies. Differences in the total haematophagus fly 2 abundance was not significant across the altitudinal levels (X2 = 0.432; P = 0.511; OR = 1.13). The relative apparent density (RAD) of 0.47, 0.22, 0.13, 0.09, 0.07 and 0.03 (flies/trap/day) was observed in Glossina, Hippobosca, Tabanus, Haematopota, Chrysops, Ancala and, respectively. The diversity index of 0.55 and 0.76 were determined for Glossina spp. and Tabanids respectively. The non-blood sucking flies in order of abundance are Musca domestica (43.6%), Fanniacanicularis (41.9%), Chrysomyia bezziana (8.9%), Lucilia sericata (5.6%). If the value-chain of ecotourism is to be promoted in the park, vector-borne arthropods need to be controlled through the use of integrated methods. Keywords: Ecological survey, haematophagus flies, Old Oyo national Park, RAD


2020 ◽  
Author(s):  
Hend H.A.M. Abdullah ◽  
Dina Aboelsoued ◽  
Tarek K Farag ◽  
Kadria N Abdel Megeed ◽  
Sobhy Abdel-Shafy ◽  
...  

Abstract Background Equine vector borne diseases (EVBD) have been considered emerging and reemerging diseases transmitted by arthropods and most of these diseases have zoonotic concern. This study was designed to screen EVBD in equines and their vectors using molecular analyses and identify vectors by MALDI-TOF and molecular techniques.Methods A total of 335 blood samples were collected from apparently healthy equines (320 from horses and 15 from donkeys) from Cairo and Beni-Suef provinces in Egypt. A total of 166 arthropods (105 sucking flies and 61 ticks) were collected from the same animals. MALDI-TOF and molecular techniques were used to confirm the findings of morphological identification of vector. Quantitative PCR and Standard PCR coupled with sequencing were performed in equines and vectors DNA for screening multiple pathogens.Results MALDI-TOF and molecular techniques confirmed that Hippoposca equina (louse fly), Rhipicephalus annulatus (Rh. annulatus) and Rh. microplus ixodid ticks were found. In vectors, we identified Anaplasma marginale (A. marginale; 1.6%), A. platys-like (1.6%) and a new Ehrlichia sp. (4.9%) in Rh. microplus, while Ehrlichia rustica (E. rustica) was found in Rh. microplus and Rh. annulatus. Likewise, Borrelia theileri was identified in Rh. microplus (3.3%). For H. equina, Anaplasma and Borrelia sp. DNA were detected by qPCR only. In equines, A. marginale (0.6%), A. ovis (0.6%) and Theileria ovis (T. ovis; 0.6%) were found in donkeys. In horses, T. equi (1.2%) and a new Theileria sp. Africa (2.7%) were identified.Conclusions For the first time, we reported here the presence of Rh. microplus as a competent tick for Rh. annulatus in Egypt using MALDI-TOF and molecular identification. To the best of our knowledge, we provided the first detection of different pathogens as A. marginale, A. platys-like, E. rustica, new Ehrlichia sp., B. theileri in Rh. microplus, A. marginale, A. ovis and T. ovis in donkeys and a new Theileria sp. Africa in horses in Egypt.


Vaccines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 10 ◽  
Author(s):  
Jessica E. Manning ◽  
Tineke Cantaert

The current increase in vector-borne disease worldwide necessitates novel approaches to vaccine development targeted to pathogens delivered by blood-feeding arthropod vectors into the host skin. A concept that is gaining traction in recent years is the contribution of the vector or vector-derived components, like salivary proteins, to host-pathogen interactions. Indeed, the triad of vector-host-pathogen interactions in the skin microenvironment can influence host innate and adaptive responses alike, providing an advantage to the pathogen to establish infection. A better understanding of this “bite site” microenvironment, along with how host and vector local microbiomes immunomodulate responses to pathogens, is required for future vaccines for vector-borne diseases. Microneedle administration of such vaccines may more closely mimic vector deposition of pathogen and saliva into the skin with the added benefit of near painless vaccine delivery. Focusing on the ‘micro’–from microenvironments to microbiomes to microneedles–may yield an improved generation of vector-borne disease vaccines in today’s increasingly complex world.


2017 ◽  
Vol 115 (5) ◽  
pp. 1009-1014 ◽  
Author(s):  
William E. Bradshaw ◽  
Joshua Burkhart ◽  
John K. Colbourne ◽  
Rudyard Borowczak ◽  
Jacqueline Lopez ◽  
...  

The spread of blood-borne pathogens by mosquitoes relies on their taking a blood meal; if there is no bite, there is no disease transmission. Although many species of mosquitoes never take a blood meal, identifying genes that distinguish blood feeding from obligate nonbiting is hampered by the fact that these different lifestyles occur in separate, genetically incompatible species. There is, however, one unique extant species with populations that share a common genetic background but blood feed in one region and are obligate nonbiters in the rest of their range: Wyeomyia smithii. Contemporary blood-feeding and obligate nonbiting populations represent end points of divergence between fully interfertile southern and northern populations. This divergence has undoubtedly resulted in genetic changes that are unrelated to blood feeding, and the challenge is to winnow out the unrelated genetic factors to identify those related specifically to the evolutionary transition from blood feeding to obligate nonbiting. Herein, we determine differential gene expression resulting from directional selection on blood feeding within a polymorphic population to isolate genetic differences between blood feeding and obligate nonbiting. We show that the evolution of nonbiting has resulted in a greatly reduced metabolic investment compared with biting populations, a greater reliance on opportunistic metabolic pathways, and greater reliance on visual rather than olfactory sensory input. W. smithii provides a unique starting point to determine if there are universal nonbiting genes in mosquitoes that could be manipulated as a means to control vector-borne disease.


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