• 1.

    Kanapathipillai R , Henao Restrepo AM , Fast P , Wood D , Dye C , Kieny MP , Moorthy V , 2014. Ebola vaccine--an urgent international priority. New Engl J Med 371: 22492251.

    • Search Google Scholar
    • Export Citation
  • 2.

    Garbutt M , Liebscher R , Wahl-Jensen V , Jones S , Möller P , Wagner R , Volchkov V , Klenk HD , Feldmann H , Ströher U , 2004. Properties of replication-competent vesicular stomatitis virus vectors expressing glycoproteins of filoviruses and arenaviruses. J Virol 78: 54585465.

    • Search Google Scholar
    • Export Citation
  • 3.

    Jones SM , Stroher U , Fernando L , Qiu X , Alimonti J , Melito P , Bray M , Klenk HD , Feldmann H , 2007. Assessment of a vesicular stomatitis virus-based vaccine by use of the mouse model of Ebola virus hemorrhagic fever. J Infect Dis 196 (Suppl 2): S404S412.

    • Search Google Scholar
    • Export Citation
  • 4.

    Jones SM et al. 2005. Live attenuated recombinant vaccine protects nonhuman primates against Ebola and Marburg viruses. Nat Med 11: 786790.

    • Search Google Scholar
    • Export Citation
  • 5.

    Geisbert TW , Feldmann H , 2011. Recombinant vesicular stomatitis virus-based vaccines against Ebola and Marburg virus infections. J Infect Dis 204 (Suppl 3): S1075S1081.

    • Search Google Scholar
    • Export Citation
  • 6.

    Geisbert TW et al. 2008. Vesicular stomatitis virus-based Ebola vaccine is well-tolerated and protects immunocompromised nonhuman primates. PLoS Pathog 4: e1000225.

    • Search Google Scholar
    • Export Citation
  • 7.

    Geisbert TW et al. 2008. Vesicular stomatitis virus-based vaccines protect nonhuman primates against aerosol challenge with Ebola and Marburg viruses. Vaccine 26: 68946900.

    • Search Google Scholar
    • Export Citation
  • 8.

    Regules JA et al. 2017. A recombinant vesicular stomatitis virus Ebola vaccine. New Engl J Med 376: 330341.

  • 9.

    Heppner DG Jr. et al. 2017. Safety and immunogenicity of the rVSVG-ZEBOV-GP Ebola virus vaccine candidate in healthy adults: a phase 1b randomised, multicentre, double-blind, placebo-controlled, dose-response study. Lancet Infect Dis 17: 854866.

    • Search Google Scholar
    • Export Citation
  • 10.

    El Sherif MS et al. 2017. Assessing the safety and immunogenicity of recombinant vesicular stomatitis virus Ebola vaccine in healthy adults: a randomized clinical trial. Can Med Assoc J 189: E819E27.

    • Search Google Scholar
    • Export Citation
  • 11.

    Coller BG et al. 2017. Clinical development of a recombinant Ebola vaccine in the midst of an unprecedented epidemic. Vaccine 35: 44654469.

    • Search Google Scholar
    • Export Citation
  • 12.

    Henao-Restrepo AM et al. 2017. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial (Ebola Ca Suffit!). Lancet 389: 505518.

    • Search Google Scholar
    • Export Citation
  • 13.

    Agnandji ST et al. 2016. Phase 1 trials of rVSV ebola vaccine in Africa and Europe. New Engl J Med 374: 16471660.

  • 14.

    Bergren NA , Miller MR , Monath TP , Kading RC , 2017. Assessment of the ability of V920 recombinant vesicular stomatitis-Zaire ebolavirus vaccine to replicate in relevant arthropod cell cultures and vector species. Hum Vaccin Immunother 14: 9941002.

    • Search Google Scholar
    • Export Citation
  • 15.

    Mead DG , Ramberg FB , Mare CJ , 2000. Laboratory vector competence of black flies (Diptera: Simuliidae) for the Indiana serotype of vesicular stomatitis virus. Ann New York Acad Sci 916: 437443.

    • Search Google Scholar
    • Export Citation
  • 16.

    Tesh RB , Chaniotis BN , Johnson KM , 1971. Vesicular stomatitis virus, Indiana serotype: multiplication in and transmission by experimentally infected phlebotomine sandflies (Lutzomyia trapidoi). Am J Epidemiol 93: 491495.

    • Search Google Scholar
    • Export Citation
  • 17.

    Tesh RB , Chaniotis BN , Johnson KM , 1972. Vesicular stomatitis virus (Indiana serotype): transovarial transmission by phlebotomine sandlies. Science 175: 14771479.

    • Search Google Scholar
    • Export Citation
  • 18.

    Webb P , Holbrook F , eds, 1989. Vesicular Stomatitis. Boca Raton, FL: CRC Press.

  • 19.

    Comer JA , Tesh RB , 1991. Phlebotomine sand flies as vectors of vesiculoviruses: a review. Parassitologia 33 (Suppl 33): 143150.

  • 20.

    Depaquit J , Grandadam M , Fouque F , Andry PE , Peyrefitte C , 2010. Arthropod-borne viruses transmitted by Phlebotomine sandflies in Europe: a review. Euro Surveillance 15: 19507.

    • Search Google Scholar
    • Export Citation
  • 21.

    Tesh RB , Modi GB , 1983. Growth and transovarial transmission of Chandipura virus (Rhabdoviridae: Vesiculovirus) in Phlebotomus papatasi. Am J Trop Med Hyg 32: 621623.

    • Search Google Scholar
    • Export Citation
  • 22.

    Doerr R , Franz K , Taussig S , 1909. Das Pappatacifieber. Leipzig, Germany.

  • 23.

    Lawyer P , Killick-Kendrick M , Rowland T , Rowton E , Volf P , 2017. Laboratory colonization and mass rearing of phlebotomine sand flies (Diptera, Psychodidae). Parasite 24: 42.

    • Search Google Scholar
    • Export Citation
  • 24.

    Hanley JA , Lippman-Hand A , 1983. If nothing goes wrong, is everything all right? Interpreting zero numerators. J Am Med Assoc 249: 17431745.

    • Search Google Scholar
    • Export Citation
  • 25.

    Theiler M , Downs WG , 1973. The Arthropod-Borne Viruses of Vertebrates. New Haven, CT and London, United Kingdom: Yale University Press.

    • Search Google Scholar
    • Export Citation
  • 26.

    Pruzinova K , Sadlova J , Seblova V , Homola M , Votypka J , Volf P , 2015. Comparison of bloodmeal digestion and the peritrophic matrix in four sand fly species differing in susceptibility to Leishmania donovani. PloS One 10: e0128203.

    • Search Google Scholar
    • Export Citation
  • 27.

    Turell MJ , Rossignol PA , Spielman A , Rossi CA , Bailey CL , 1984. Enhanced arboviral transmission by mosquitoes that concurrently ingested microfilariae. Science 225: 10391041.

    • Search Google Scholar
    • Export Citation
  • 28.

    Dostalova A , Volf P , 2012. Leishmania development in sand flies: parasite-vector interactions overview. Parasit Vectors 5: 276.

  • 29.

    Weaver SC , Lorenz LH , Scott TW , 1992. Pathologic changes in the midgut of Culex tarsalis following infection with Western equine encephalomyelitis virus. Am J Trop Med Hyg 47: 691701.

    • Search Google Scholar
    • Export Citation
  • 30.

    Darchenkova NN , Dergacheva TI , Zherikhina II , 1992. The spread of Phlebotomus papatasi Scop., 1786 through the territory of Central Asia and southern Kazakhstan. Med Parazitol 4: 3033.

    • Search Google Scholar
    • Export Citation
  • 31.

    Hassan MM , Widaa SO , Osman OM , Numiary MS , Ibrahim MA , Abushama HM , 2012. Insecticide resistance in the sand fly, Phlebotomus papatasi from Khartoum state, Sudan. Parasit Vectors 5: 46.

    • Search Google Scholar
    • Export Citation
Past two years Past Year Past 30 Days
Abstract Views 472 44 0
Full Text Views 380 134 19
PDF Downloads 144 76 15
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

No Evidence of rVSV-Ebola Virus Vaccine Replication or Dissemination in the Sand Fly Phlebotomus papatasi

Andrew D. Haddow United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland;

Search for other papers by Andrew D. Haddow in
Current site
Google Scholar
PubMed
Close
,
Tobin E. Rowland Walter Reed Army Institute of Research, Silver Spring, Maryland;

Search for other papers by Tobin E. Rowland in
Current site
Google Scholar
PubMed
Close
,
Sarah L. Norris United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland;

Search for other papers by Sarah L. Norris in
Current site
Google Scholar
PubMed
Close
,
Thomas R. Sprague United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland;

Search for other papers by Thomas R. Sprague in
Current site
Google Scholar
PubMed
Close
,
Jorge O. Lopez Walter Reed Army Institute of Research, Silver Spring, Maryland;

Search for other papers by Jorge O. Lopez in
Current site
Google Scholar
PubMed
Close
,
Mark C. Carder Walter Reed Army Institute of Research, Silver Spring, Maryland;

Search for other papers by Mark C. Carder in
Current site
Google Scholar
PubMed
Close
,
Yvonne-Marie Linton Walter Reed Biosystematics Unit, Smithsonian Museum Support Center, Suitland, Maryland;
Department of Entomology, Smithsonian Institution National Museum of Natural History, Washington, District of Columbia

Search for other papers by Yvonne-Marie Linton in
Current site
Google Scholar
PubMed
Close
, and
M. Louise M. Pitt United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, Maryland;

Search for other papers by M. Louise M. Pitt in
Current site
Google Scholar
PubMed
Close

ABSTRACT

Following vaccination with the live attenuated, recombinant vesicular stomatitis virus Indiana serotype Ebola virus (rVSV-EBOV) vaccine, persons may exhibit a transient vaccine-associated viremia. To investigate the potential for Old World sand flies to transmit this vaccine following feeding on a viremic person, we fed laboratory-reared Phlebotomus papatasi an artificial blood meal containing 7.2 log10 plaque-forming units of rVSV-EBOV. Replication or dissemination was not detected in the body or legs of any P. papatasi collected at seven (n = 75) or 15 (n = 75) days post-feed. These results indicate a low potential for rVSV-EBOV to replicate and disseminate in P. papatasi, a species whose geographic distribution ranges from Morocco to southwest Asia and as far north as southern Europe.

The largest Ebola virus (EBOV: family Filoviridae, genus Ebolavirus) outbreak in recorded history began in West Africa in December 2014. This outbreak resulted in more than 11,000 deaths and highlighted the critical need for an Food and Drug Administration-approved vaccine to interrupt virus transmission. One such candidate is the live, attenuated recombinant vesicular stomatitis virus Indiana serotype EBOV (rVSV-EBOV) vaccine. 1 This live attenuated vaccine is a recombinant VSV (family Rhabdoviridae, genus Vesiculovirus) based on the Indiana serotype which has been genetically engineered to express the transmembrane glycoprotein of EBOV. 27 Clinical trials demonstrated that the rVSV-EBOV vaccine was immunogenic and well-tolerated in healthy adults, 810 and this vaccine was used during the 2014–2016 EBOV disease outbreak in West Arica, 11,12 as well as the recent and current EBOV outbreaks in the Democratic Republic of Congo.

Following vaccination with rVSV-EBOV, some persons may develop a transient vaccine-associated viremia with peak levels of approximately 3.0 log10 plaque-forming units (PFU)/mL. 8,13 A previous study found no evidence of rVSV-ZEBOV replication or dissemination in Aedes aegypti (Linnaeus) or Culex quinquefasciatus Say (Diptera: Culicidae) fed with a high-titer, artificial blood meal; or detected replication in mosquito (Ae. albopictus [C6/36] or Anopheles gambiae Giles [4a4b]), midge Culicoides variipennis (Coquillett) (CuVa), or sand fly Lutzomyia longipalpis (Lutz and Neivai) (LL-5) cell lines. 14 However, sand flies and blackflies are the considered primary vectors of VSV-Indiana in nature. 1519 Therefore, we assessed the susceptibility of Phlebotomus papatasi Scopoli (Diptera: Psychodidae), an anthropophilic sand fly known to transmit viruses within the VSV serogroup, 1922 to become infected with rVSV-EBOV following consumption of an artificial infectious blood meal.

Seven-day-old, laboratory-reared P. papatasi sand flies maintained in colony since 2004 (Origin: Akbuk, Turkey) 23 were sugar-starved for 24 hours and then allowed to feed for 1 hour on an artificial blood meal composed of one part rVSV-EBOV to six parts defibrinated rabbit blood (LAMPIRE Biological Laboratories, Pipersville, PA) contained in glass membrane feeders (Lillie Glassblowers, Atlanta, GA) covered in chicken skins. A portion of the artificial blood meal was frozen at −80°C to perform back titration by plaque assay. Because of their delicate peritrophic membrane, which is susceptible to rupture from handling, sand flies were sorted 24 hours post-blood feed, and only those sand flies which were blood-engorged were retained. 23 Sand flies were then maintained in a 12:12-hour light/dark cycle at 25°C, 80% relative humidity, in a 30% sucrose solution via cotton ball for the duration of the experiment. An exemplar DNA barcode (658 bp of the mitochondrial deoxyribonucleic acid cytochrome c oxidase I gene) was used to confirm and document species identity (GenBank accession MH780862). This sequence shares 99.2% homology with the full mitochondrial genome of P. papatasi (GenBank accession KR349298).

On days 7 and 15 post-exposure, 75 flies were collected to test for the presence of stable or replicating rVSV-EBOV. This sample size achieved an 80% power to detect a difference (P 1P 0) of 0.0593 using a one-sided binomial exact test with a target significance level of 0.05 for each time point, assuming the population proportion under the null hypothesis (P 0) is 0.013. The upper 95% confidence limit of the population proportion was estimated using Hanley’s rule of three ( 1 maximum population proportion = 0.05 n ) for sand flies collected at both time points. 24 Sand flies were chilled to immobilize, then dissected, and homogenized (legs and body separately) in tubes containing a 5 mm stainless steel bead (QIAGEN, Hilden, Germany) and 500 μL of Dulbecco’s modified Eagle medium (DMEM: Corning Life Sciences, Tewksbury, MA), supplemented with 20% volume/volume (v/v) fetal bovine serum (HyClone, GE Healthcare, Logan, UT), 50.0 μg/mL gentamicin (Gibco, Carlsbad, CA), and 0.5 mg/mL amphotericin B (Sigma Aldrich, St. Louis, MO) and frozen at −80°C. Before virus titration by plaque assay, tubes were thawed and homogenized using a QIAGEN TissueLyser II (QIAGEN) for 5 minutes at 26 Hz, after which they were centrifuged at 13,000 revolutions per minute for 10 minutes at 4°C, and supernatant was collected.

Titration of vaccine and sand fly supernatants was performed on Vero cells (CCL-81, ATCC, Manassas, VA) by plaque assay. Briefly, duplicate cell wells were inoculated with serial 10-fold dilutions of the supernatant prepared in DMEM, supplemented with 50.0 μg/mL gentamicin, 1.0 mM sodium pyruvate (Sigma Aldrich), 1% v/v nonessential amino acids (Sigma Aldrich), and 0.5 mg/mL amphotericin B (Sigma Aldrich). We also included positive and negative controls. Vaccine or sand fly supernatant was allowed to absorb for 1 hour at 37°C and was overlaid with 3.0 mL of 1% weight/volume Sea-Plaque agarose (Cambrex Bio Science, East Rutherford, NJ) in DMEM. Cells were incubated at 37°C (5% CO2) for 2 days (vaccine plaque assay) and 4 days (sand fly supernatant plaque assay). Following incubation, cells were fixed using 4% formaldehyde (Fisher Scientific, Waltham, MA) in phosphate-buffered saline (phosphate buffered saline; Corning Life Sciences). After 24 hours, the overlay was removed, and cells were stained using 2% crystal violet (Sigma Aldrich) in 70% methanol (Sigma Aldrich). Plaques were counted, and the results were reported as the number of PFU/mL. The limit of detection of the plaque assay was 1.0 log10 PFU/mL.

Although the ecology of VSV-Indiana is somewhat obscure, 18,25 New World sand flies of the genus Lutzomyia (Diptera: Psychodidae) are considered a primary virus vector. 16,17,19 As EBOV is known to circulate in Africa, we used P. papatasi to model the potential for Old World sand flies of the genus Phlebotomus to transmit rVSV-EBOV after feeding on a person with vaccine-associated viremia. Following the feeding of P. papatasi on an artificial blood meal containing 7.2 log10 PFU of rVSV-EBOV, we did not detect infectious rVSV-EBOV in the body or legs of any sand fly collected at seven (n = 75) or 15 (n = 75) days post-feed. Given that the observed proportion was 0.0, the true proportion can be estimated with 95% confidence to be no greater than 0.039 based on Hanley’s rule of three for sand flies collected at both time points.

The refractoriness of P. papatasi to an estimated per sand fly rVSV-EBOV dose ranging from 4.0 to 4.1 log10 PFU indicates a low potential for rVSV-EBOV vaccine replication and dissemination following feeding on a person who developed a moderate, post-vaccination viremia. 8,13,26 However, the possibility of infection and dissemination in P. papatasi following the oral feeding of a higher dose of rVSV-EBOV cannot be ruled out. Furthermore, the sand flies used in this experiment had biologically unaltered intact midguts, whereas in nature, the possibility exists that parasitic or arboviral infections could result in damage to the midgut barrier. 2729 Therefore, future experiments are needed to evaluate the risk for vaccine replication in the salivary glands of P. papatasi.

Nonetheless, our results indicate the rVSV vaccine platform could potentially be used to develop vaccines for other viruses of medical and veterinary importance that circulate in regions where P. papatasi has been reported—Morocco to southwest Asia and as far north as southern Europe. 20,30,31

REFERENCES

  • 1.

    Kanapathipillai R , Henao Restrepo AM , Fast P , Wood D , Dye C , Kieny MP , Moorthy V , 2014. Ebola vaccine--an urgent international priority. New Engl J Med 371: 22492251.

    • Search Google Scholar
    • Export Citation
  • 2.

    Garbutt M , Liebscher R , Wahl-Jensen V , Jones S , Möller P , Wagner R , Volchkov V , Klenk HD , Feldmann H , Ströher U , 2004. Properties of replication-competent vesicular stomatitis virus vectors expressing glycoproteins of filoviruses and arenaviruses. J Virol 78: 54585465.

    • Search Google Scholar
    • Export Citation
  • 3.

    Jones SM , Stroher U , Fernando L , Qiu X , Alimonti J , Melito P , Bray M , Klenk HD , Feldmann H , 2007. Assessment of a vesicular stomatitis virus-based vaccine by use of the mouse model of Ebola virus hemorrhagic fever. J Infect Dis 196 (Suppl 2): S404S412.

    • Search Google Scholar
    • Export Citation
  • 4.

    Jones SM et al. 2005. Live attenuated recombinant vaccine protects nonhuman primates against Ebola and Marburg viruses. Nat Med 11: 786790.

    • Search Google Scholar
    • Export Citation
  • 5.

    Geisbert TW , Feldmann H , 2011. Recombinant vesicular stomatitis virus-based vaccines against Ebola and Marburg virus infections. J Infect Dis 204 (Suppl 3): S1075S1081.

    • Search Google Scholar
    • Export Citation
  • 6.

    Geisbert TW et al. 2008. Vesicular stomatitis virus-based Ebola vaccine is well-tolerated and protects immunocompromised nonhuman primates. PLoS Pathog 4: e1000225.

    • Search Google Scholar
    • Export Citation
  • 7.

    Geisbert TW et al. 2008. Vesicular stomatitis virus-based vaccines protect nonhuman primates against aerosol challenge with Ebola and Marburg viruses. Vaccine 26: 68946900.

    • Search Google Scholar
    • Export Citation
  • 8.

    Regules JA et al. 2017. A recombinant vesicular stomatitis virus Ebola vaccine. New Engl J Med 376: 330341.

  • 9.

    Heppner DG Jr. et al. 2017. Safety and immunogenicity of the rVSVG-ZEBOV-GP Ebola virus vaccine candidate in healthy adults: a phase 1b randomised, multicentre, double-blind, placebo-controlled, dose-response study. Lancet Infect Dis 17: 854866.

    • Search Google Scholar
    • Export Citation
  • 10.

    El Sherif MS et al. 2017. Assessing the safety and immunogenicity of recombinant vesicular stomatitis virus Ebola vaccine in healthy adults: a randomized clinical trial. Can Med Assoc J 189: E819E27.

    • Search Google Scholar
    • Export Citation
  • 11.

    Coller BG et al. 2017. Clinical development of a recombinant Ebola vaccine in the midst of an unprecedented epidemic. Vaccine 35: 44654469.

    • Search Google Scholar
    • Export Citation
  • 12.

    Henao-Restrepo AM et al. 2017. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial (Ebola Ca Suffit!). Lancet 389: 505518.

    • Search Google Scholar
    • Export Citation
  • 13.

    Agnandji ST et al. 2016. Phase 1 trials of rVSV ebola vaccine in Africa and Europe. New Engl J Med 374: 16471660.

  • 14.

    Bergren NA , Miller MR , Monath TP , Kading RC , 2017. Assessment of the ability of V920 recombinant vesicular stomatitis-Zaire ebolavirus vaccine to replicate in relevant arthropod cell cultures and vector species. Hum Vaccin Immunother 14: 9941002.

    • Search Google Scholar
    • Export Citation
  • 15.

    Mead DG , Ramberg FB , Mare CJ , 2000. Laboratory vector competence of black flies (Diptera: Simuliidae) for the Indiana serotype of vesicular stomatitis virus. Ann New York Acad Sci 916: 437443.

    • Search Google Scholar
    • Export Citation
  • 16.

    Tesh RB , Chaniotis BN , Johnson KM , 1971. Vesicular stomatitis virus, Indiana serotype: multiplication in and transmission by experimentally infected phlebotomine sandflies (Lutzomyia trapidoi). Am J Epidemiol 93: 491495.

    • Search Google Scholar
    • Export Citation
  • 17.

    Tesh RB , Chaniotis BN , Johnson KM , 1972. Vesicular stomatitis virus (Indiana serotype): transovarial transmission by phlebotomine sandlies. Science 175: 14771479.

    • Search Google Scholar
    • Export Citation
  • 18.

    Webb P , Holbrook F , eds, 1989. Vesicular Stomatitis. Boca Raton, FL: CRC Press.

  • 19.

    Comer JA , Tesh RB , 1991. Phlebotomine sand flies as vectors of vesiculoviruses: a review. Parassitologia 33 (Suppl 33): 143150.

  • 20.

    Depaquit J , Grandadam M , Fouque F , Andry PE , Peyrefitte C , 2010. Arthropod-borne viruses transmitted by Phlebotomine sandflies in Europe: a review. Euro Surveillance 15: 19507.

    • Search Google Scholar
    • Export Citation
  • 21.

    Tesh RB , Modi GB , 1983. Growth and transovarial transmission of Chandipura virus (Rhabdoviridae: Vesiculovirus) in Phlebotomus papatasi. Am J Trop Med Hyg 32: 621623.

    • Search Google Scholar
    • Export Citation
  • 22.

    Doerr R , Franz K , Taussig S , 1909. Das Pappatacifieber. Leipzig, Germany.

  • 23.

    Lawyer P , Killick-Kendrick M , Rowland T , Rowton E , Volf P , 2017. Laboratory colonization and mass rearing of phlebotomine sand flies (Diptera, Psychodidae). Parasite 24: 42.

    • Search Google Scholar
    • Export Citation
  • 24.

    Hanley JA , Lippman-Hand A , 1983. If nothing goes wrong, is everything all right? Interpreting zero numerators. J Am Med Assoc 249: 17431745.

    • Search Google Scholar
    • Export Citation
  • 25.

    Theiler M , Downs WG , 1973. The Arthropod-Borne Viruses of Vertebrates. New Haven, CT and London, United Kingdom: Yale University Press.

    • Search Google Scholar
    • Export Citation
  • 26.

    Pruzinova K , Sadlova J , Seblova V , Homola M , Votypka J , Volf P , 2015. Comparison of bloodmeal digestion and the peritrophic matrix in four sand fly species differing in susceptibility to Leishmania donovani. PloS One 10: e0128203.

    • Search Google Scholar
    • Export Citation
  • 27.

    Turell MJ , Rossignol PA , Spielman A , Rossi CA , Bailey CL , 1984. Enhanced arboviral transmission by mosquitoes that concurrently ingested microfilariae. Science 225: 10391041.

    • Search Google Scholar
    • Export Citation
  • 28.

    Dostalova A , Volf P , 2012. Leishmania development in sand flies: parasite-vector interactions overview. Parasit Vectors 5: 276.

  • 29.

    Weaver SC , Lorenz LH , Scott TW , 1992. Pathologic changes in the midgut of Culex tarsalis following infection with Western equine encephalomyelitis virus. Am J Trop Med Hyg 47: 691701.

    • Search Google Scholar
    • Export Citation
  • 30.

    Darchenkova NN , Dergacheva TI , Zherikhina II , 1992. The spread of Phlebotomus papatasi Scop., 1786 through the territory of Central Asia and southern Kazakhstan. Med Parazitol 4: 3033.

    • Search Google Scholar
    • Export Citation
  • 31.

    Hassan MM , Widaa SO , Osman OM , Numiary MS , Ibrahim MA , Abushama HM , 2012. Insecticide resistance in the sand fly, Phlebotomus papatasi from Khartoum state, Sudan. Parasit Vectors 5: 46.

    • Search Google Scholar
    • Export Citation

Author Notes

Address correspondence to Andrew D. Haddow, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), 1425 Porter St., Frederick, MD 21701. E-mail: andrew.d.haddow.ctr@mail.mil

Disclaimer: The views expressed in this article are those of the authors and do not represent the official policy or position of the U.S. Department of the Army, Department of Defense, or the U.S. government.

Financial support: This study was funded by the Defense Threat Reduction Agency (DTRA).

Authors’ addresses: Andrew D. Haddow, Department of Virology, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, E-mail: andrew.d.haddow.ctr@mail.mil. Tobin E. Rowland, Jorge O. Lopez, and Mark C. Carder, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, E-mails: tobin.e.rowland.civ@mail.mil, jorge.o.lopez8.mil@mail.mil, and mark.c.carder.mil@mail.mil. Sarah L. Norris, Department of Biostatistics, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, E-mail: sarah.l.norris2.civ@mail.mil. Thomas R. Sprague, Department of Virology, US Army Medical Research and Materiel Command, Frederick, MD, E-mail: thomas.r.sprague7.ctr@mail.mil. Yvonne-Marie Linton, Department of Entomology, Walter Reed Biosystematics Unit, Suitland, MD, E-mail: linton.yvonne3@gmail.com. M. Louise M. Pitt, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, E-mail: margaret.l.pitt.civ@mail.mil.

Save