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1.
BMC Health Serv Res ; 23(1): 1321, 2023 Nov 29.
Article in English | MEDLINE | ID: mdl-38031166

ABSTRACT

BACKGROUND: A disproportionate burden of maternal deaths occurs in low- and middle-income countries (LMICs), and obstetric hemorrhage (OH) is a leading cause of excess mortality. In Zambia, most of maternal deaths are directly caused by OH. The Non-Pneumatic Anti-Shock Garment (NASG) is a first aid tool that uses compression to the abdomen and lower body to stop and reverse hypovolemic shock secondary to OH. We describe the process and experiences introducing the NASG into the Zambia public health system to encourage the development of national policies, clinical guidelines, and implementation plans that feature the NASG. METHODS: We conducted an observational study of NASG introduction to 143 public health facilities in Northern Province, Zambia, organizing observations into the five dimensions of the RE-AIM evaluation framework: reach, effectiveness, adoption, implementation, and maintenance. The NASG was introduced in August 2019, and the introduction was evaluated for 18 months. Data on healthcare worker training and mentorship, cases where NASG was used, and NASG availability and use during the study period were collected and analyzed. RESULTS: The NASG was successfully introduced and integrated into the Zambia public health system, and appropriately used by healthcare workers when responding to cases of OH. Sixteen months after NASG introduction, NASGs were available and functional at 99% of study sites and 88% reported ever using a NASG. Of the 68 cases of recorded OH where a NASG was applied, 66 were confirmed as clinically appropriate, and among cases where shock index (SI) could be calculated, 59% had SI ≥ 0.9. Feedback from healthcare providers revealed that 97% thought introducing the NASG was a good decision, and 92% felt confident in their ability to apply the NASG after initial training. The RE-AIM average for this study was 0.65, suggesting a public health impact that is not equivocal, and that NASG introduction had a positive population-based effect. CONCLUSIONS: A successful NASG demonstration took place over the course of 18 months in the existing health system of Northern Province, Zambia, suggesting that incorporation of NASG into the standard of care for obstetric emergency in the Zambia public sector is feasible and can be maintained without external support.


Subject(s)
Maternal Death , Postpartum Hemorrhage , Shock , Pregnancy , Female , Humans , Zambia , Public Health , Shock/therapy , Shock/etiology , Clothing
2.
Int Health ; 2023 Oct 03.
Article in English | MEDLINE | ID: mdl-37787149

ABSTRACT

Benzathine benzylpenicillin is a globally indispensable medicine. As a long-lasting injectable penicillin, it serves as the primary treatment for syphilis, group A streptococcal infections, rheumatic fever and rheumatic heart disease. A competitive market and low profit margins, compounded by limited visibility of demand, have resulted in a decreased number of active pharmaceutical ingredient (API) manufacturers. By 2016, only three Chinese API manufacturers remained, continuing to supply to the global market today. Recurring global shortages, a consequence of supply and demand imbalances, indicate underlying market risks. Therefore, the need for mitigation strategies is imperative.

3.
PLOS Glob Public Health ; 2(12): e0001162, 2022.
Article in English | MEDLINE | ID: mdl-36962888

ABSTRACT

Reducing maternal and neonatal mortality is a critical health priority within Zambia and globally. Although evidence-based clinical interventions can prevent a majority of these deaths, scalable and sustainable delivery of interventions across low-resource settings remains uneven, particularly across rural and marginalized communities. The Zambian Ministry of Health and the Clinton Health Access Initiative implemented an integrated sexual, reproductive, maternal, and newborn health (SRMNH) program in Northern Province aimed at dramatically reducing mortality over four years. Interventions were implemented between 2018 and 2021 across 141 government-owned health facilities covering all 12 districts of Northern Province, the poorest performing province nationwide and home to over 1.4 million people, around six pillars of an integrated health system. Data on institutional delivery and antenatal and postnatal care were collected through the national Health Management Information System (HMIS). A community-based system for capturing birth outcomes was established using existing government tools and community volunteers since HMIS did not include community-based mortality. Baseline and endline population-based mortality rates were compared for program-supported areas. From the earliest period of population-based mortality reporting in 2019 to program end in 2021, there were statistically significant decreases of 41%, 45%, and 43% in maternal, neonatal, and perinatal mortality rates respectively. Between 2017 to 2021, institutional maternal, neonatal, and perinatal mortality rates across entirety of Northern Province reduced by 12%, 40%, and 41%, respectively. Service readiness and coverage for SRMNH services improved dramatically, supporting increased numbers of patients. Significant mortality reductions were achieved over a relatively short period, reinforced through an emphasis on sustainability and strengthening existing government systems. These results were attained through a consciously cost-efficient approach backed by substantially lower levels of external investment relative to prior programs, allowing many of the interventions to be successfully adopted by government within public sector budgets.

4.
PLoS One ; 16(8): e0256400, 2021.
Article in English | MEDLINE | ID: mdl-34411167

ABSTRACT

BACKGROUND: WHO recommends use of rapid dual HIV/syphilis tests for screening pregnant women (PW) during antenatal care to prevent mother-to-child transmission. Scale-up of testing implies a need to accurately forecast and procure benzathine penicillin (BPG) to treat the additionally identified PW with syphilis. METHODS: Country-reported ANC coverage, PW syphilis screening and treatment coverage values in 2019 were scaled linearly to EMTCT targets by 2030 (constant increasing slope from 2019 figures to 95% in 2030) for 11 focus countries. Antenatal syphilis screening coverage was substituted with HIV screening coverage to estimate potential contribution of rapid dual HIV/syphilis tests in identifying additional PW with syphilis. BPG demand was calculated for 2019-2030 accordingly. RESULTS: The estimated demand for BPG (in 2.4 million unit vials) using current maternal syphilis prevalence and treatment coverage will increase from a baseline of 414,459 doses in 2019 to 683,067 doses (+65%) in 2021 assuming immediate replacement of single HIV test kits with rapid dual HIV/syphilis tests for these 11 countries. Continued scale up of syphilis screening and treatment coverage to reach elimination coverage of 95% will result in an estimated demand increase of 160%, (663,969 doses) from 2019 baseline for a total demand of 1,078,428 BPG doses by 2030. CONCLUSIONS: Demand for BPG will increase following adoption of rapid dual HIV/syphilis test kits due to increases in maternal diagnoses of syphilis. To eliminate congenital syphilis, MNCH clinical programs will need to synergize with disease surveillance programs to accurately forecast BPG demand with scale up of antenatal syphilis screening to ensure adequate treatment is available for pregnant women diagnosed with syphilis.


Subject(s)
Syphilis, Congenital , Adult , Female , Humans , Infectious Disease Transmission, Vertical , Pregnancy , Pregnancy Complications, Infectious
5.
J Int AIDS Soc ; 24(4): e25686, 2021 04.
Article in English | MEDLINE | ID: mdl-33787064

ABSTRACT

INTRODUCTION: HIV retesting during late pregnancy and breastfeeding can help detect new maternal infections and prevent mother-to-child HIV transmission (MTCT), but the optimal timing and cost-effectiveness of maternal retesting remain uncertain. METHODS: We constructed deterministic models to assess the health and economic impact of maternal HIV retesting on a hypothetical population of pregnant women, following initial testing in pregnancy, on MTCT in four countries: South Africa and Kenya (high/intermediate HIV prevalence), and Colombia and Ukraine (low HIV prevalence). We evaluated six scenarios with varying retesting frequencies from late in antenatal care (ANC) through nine months postpartum. We compared strategies using incremental cost-effectiveness ratios (ICERs) over a 20-year time horizon using country-specific thresholds. RESULTS: We found maternal retesting once in late ANC with catch-up testing through six weeks postpartum was cost-effective in Kenya (ICER = $166 per DALY averted) and South Africa (ICER=$289 per DALY averted). This strategy prevented 19% (Kenya) and 12% (South Africa) of infant HIV infections. Adding one or two additional retests postpartum provided smaller benefits (1 to 2 percentage point increase in infections averted versus one retest). Adding three retests during the postpartum period averted additional infections (1 to 3 percentage point increase in infections averted versus one retest) but ICERs ($7639 and in Kenya and $11 985 in South Africa) greatly exceeded the cost-effectiveness thresholds. In Colombia and Ukraine, all retesting strategies exceeded the cost-effectiveness threshold and prevented few infant infections (up to 31 and 5 infections, respectively). CONCLUSIONS: In high HIV burden settings with MTCT rates similar to those seen in Kenya and South Africa, HIV retesting once in late ANC, with subsequent intervention, is the most cost-effective strategy for preventing infant HIV infections. In these settings, two HIV retests postpartum marginally reduced MTCT and were less costly than adding three retests. Retesting in low-burden settings with MTCT rates similar to Colombia and Ukraine was not cost-effective at any time point due to very low HIV prevalence and limited breastfeeding.


Subject(s)
HIV Infections/diagnosis , HIV Testing/economics , Infectious Disease Transmission, Vertical/prevention & control , Pregnancy Complications, Infectious/diagnosis , Cost-Benefit Analysis , Female , HIV Infections/epidemiology , HIV Infections/prevention & control , HIV Testing/methods , Humans , Infant , Postpartum Period , Pregnancy , Pregnancy Complications, Infectious/epidemiology , Pregnancy Complications, Infectious/prevention & control , Prevalence
6.
Lancet Glob Health ; 9(1): e61-e71, 2021 01.
Article in English | MEDLINE | ID: mdl-33227254

ABSTRACT

BACKGROUND: Dual HIV and syphilis testing might help to prevent mother-to-child transmission (MTCT) of HIV and syphilis through increased case detection and treatment. We aimed to model and assess the cost-effectiveness of dual testing during antenatal care in four countries with varying HIV and syphilis prevalence. METHODS: In this modelling study, we developed Markov models of HIV and syphilis in pregnant women to estimate costs and infant health outcomes of maternal testing at the first antenatal care visit with individual HIV and syphilis tests (base case) and at the first antenatal care visit with a dual rapid diagnostic test (scenario one). We additionally evaluated retesting during late antenatal care and at delivery with either individual tests (scenario two) or a dual rapid diagnosis test (scenario three). We modelled four countries: South Africa, Kenya, Colombia, and Ukraine. Strategies with an incremental cost-effectiveness ratio (ICER) less than the country-specific cost-effectiveness threshold (US$500 in Kenya, $750 in South Africa, $3000 in Colombia, and $1000 in Ukraine) per disability-adjusted life-year averted were considered cost-effective. FINDINGS: Routinely offering testing at the first antenatal care visit with a dual rapid diagnosis test was cost-saving compared with the base case in all four countries (ICER: -$26 in Kenya,-$559 in South Africa, -$844 in Colombia, and -$454 in Ukraine). Retesting during late antenatal care with a dual rapid diagnostic test (scenario three) was cost-effective compared with scenario one in all four countries (ICER: $270 in Kenya, $260 in South Africa, $2207 in Colombia, and $205 in Ukraine). INTERPRETATION: Incorporating dual rapid diagnostic tests in antenatal care can be cost-saving across countries with varying HIV prevalence. Countries should consider incorporating dual HIV and syphilis rapid diagnostic tests as the first test in antenatal care to support efforts to eliminate MTCT of HIV and syphilis. FUNDING: WHO, US Agency for International Development, and the Bill & Melinda Gates Foundation.


Subject(s)
Cost-Benefit Analysis/statistics & numerical data , HIV Infections/diagnosis , HIV Infections/epidemiology , Pregnancy Complications, Infectious/diagnosis , Prenatal Diagnosis/methods , Syphilis/diagnosis , Adult , Colombia/epidemiology , Cost-Benefit Analysis/economics , Cost-Benefit Analysis/methods , Female , HIV Infections/economics , Humans , Infectious Disease Transmission, Vertical/economics , Infectious Disease Transmission, Vertical/prevention & control , Kenya/epidemiology , Markov Chains , Models, Theoretical , Pregnancy , Pregnancy Complications, Infectious/economics , Prenatal Diagnosis/economics , Prevalence , South Africa/epidemiology , Syphilis/economics , Ukraine/epidemiology
7.
Health Syst Reform ; 6(2): e1841450, 2020 09 01.
Article in English | MEDLINE | ID: mdl-33270477

ABSTRACT

In Nigeria, two maternal and neonatal health Networks of Care (NOC) focus on extending the reach and quality of routine and emergency maternal and neonatal health services tailored to the different contexts. This paper uses the four domains of the NOC framework-Agreements and Enabling Environment, Operational Standards, Quality, Efficiency and Responsibility, and Learning and Adaptation-to describe the NOC, highlighting how each developed to address specific local needs. In Northern Nigeria, the NOC were established in collaboration among Clinton Health Access Initiative and the government to reduce maternal and neonatal morbidity and mortality. Health centers and communities in the network were supported to be better prepared to provide maternal and neonatal care, while birth attendants at all levels were empowered and equipped to stabilize and treat complications. The approach brought services closer to the community and facilitated rapid referrals. The NOC in Lagos State extended the reach of routine and emergency maternal and neonatal health services through organically developed linkages among registered traditional birth attendant clinics, private and public sector facilities, the Primary Healthcare Board, and the Traditional Medicine Board. Traditional birth attendants are registered, trained, and monitored by Apex Community Health Officers, whose responsibilities include collection and review of data and ensuring linkages to postpartum services, such as family planning and immunizations. While differing in their approaches, both NOC provide locally appropriate, pragmatic approaches to supporting women birthing in the community and encouraging institutional delivery to ensure that women and their babies have access to timely, appropriate, and safe services.


Subject(s)
Community Networks/trends , Maternal-Child Health Services/trends , Patient-Centered Care/methods , Humans , Nigeria , Patient-Centered Care/trends
8.
Health Syst Reform ; 6(2): e1810921, 2020 09 25.
Article in English | MEDLINE | ID: mdl-33021881

ABSTRACT

The phrase "Networks of Care" seems familiar but remains poorly defined. A health system that exemplifies effective Networks of Care (NOC) purposefully and effectively interconnects service delivery touch points within a catchment area to fill critical service gaps and create continuity in patient care. To more fully elaborate the concept of Networks of Care, we conducted a multi-method scoping study that included a literature review, stakeholder interviews, and descriptive case studies from five low- and middle-income countries. Our extended definition of a Network of Care features four overlapping and interdependent domains of activity at multiple levels of health systems, characterized by: 1) Agreement and Enabling Environment, 2) Operational Standards, 3) Quality, Efficiency and Responsibility, and 4) Learning and Adaptation. There are a series of key interrelated themes within each domain. Creating a common understanding of what characterizes and fosters an effective Network of Care can drive the evolution and strengthening of national health programs, especially those incorporating universal health coverage and promoting comprehensive care and integrated services. An understanding of the Networks of Care model can help guide efforts to move health service delivery toward goals that can benefit a diversity of stakeholders, including a variety of health system actors, such as health care workers, users of health systems, and the wider community at large. It can also contribute to improving poor health outcomes and reducing waste originating from fragmented services and lack of access.


Subject(s)
Community Networks/trends , Cooperative Behavior , Delivery of Health Care/methods , Delivery of Health Care/trends , Humans
10.
Matern Child Health J ; 22(7): 986-997, 2018 07.
Article in English | MEDLINE | ID: mdl-29427018

ABSTRACT

Introduction Nigeria contributes more obstetric, postpartum and neonatal deaths and stillbirths globally than any other country. The Clinton Health Access Initiative in partnership with the Nigerian Federal Ministry of Health and the state Governments of Kano, Katsina, and Kaduna implemented an integrated Maternal and Neonatal Health program from July 2014. Up to 90% women deliver at home in Northern Nigeria, where maternal mortality ratio and neonatal mortality rates (MMR and NMR) are high and severe challenges to improving survival exist. Methods Community-based leaders ("key informants") reported monthly vital events. Pre-post comparisons of later (months 16-18) with conservative baseline (months 7-9) rates were used to assess change in MMR, NMR, perinatal mortality (PMR) and stillbirth. Two-tailed cross-tabulations and unadjusted and adjusted logistic regression analyses were conducted. Results Data on 147,455 births (144,641 livebirths and 4275 stillbirths) were analyzed. At endline (months 16-18), MMR declined 37% (OR 0.629, 95% CI 0.490-0.806, p ≤ 0.0003) vs. baseline 440/100,000 births (months 7-9). NMR declined 43% (OR 0.574, 95% CI 0.503-0.655, p < 0.0001 vs. baseline 15.2/1000 livebirths. Stillbirth rates declined 15% (OR 0.850, 95% CI 0.768-0.941, p = 0.0018) vs. baseline 21.1/1000 births. PMR declined 27% (OR 0.733, 95% CI 0.676-0.795, p < 0.0001) vs. baseline 36.0/1000 births. Adjusted results were similar. Discussion The findings are similar to the Cochrane Review effects of community-based interventions and indicate large survival improvements compared to much slower global and flat national trends. Key informant data have limitations, however, their limitations would have little effect on the results magnitude or significance.


Subject(s)
Infant Mortality , Maternal Mortality , Perinatal Death , Program Evaluation/methods , Stillbirth/epidemiology , Adult , Female , Humans , Infant , Infant Mortality/trends , Infant, Newborn , Male , Maternal Mortality/trends , Nigeria/epidemiology , Pregnancy , Pregnancy Outcome/epidemiology , Survival Rate/trends
11.
Anal Chim Acta ; 952: 1-8, 2017 02 01.
Article in English | MEDLINE | ID: mdl-28010838

ABSTRACT

A new direct-current microplasma-based flowing atmospheric pressure afterglow (FAPA) source was developed for use in ambient desorption-ionization mass spectrometry. The annular-shaped microplasma is formed in helium between two concentric stainless-steel capillaries that are separated by an alumina tube. Current-voltage characterization of the source shows that this version of the FAPA operates in the normal glow-discharge regime. A glass surface placed in the path of the helium afterglow reaches temperatures of up to approximately 400 °C; the temperature varies with distance from the source and helium flow rate through the source. Solid, liquid, and vapor samples were examined by means of a time-of-flight mass spectrometer. Results suggest that ionization occurs mainly through protonation, with only a small amount of fragmentation and adduct formation. The mass range of the source was shown to extend up to at least m/z 2722 for singly charged species. Limits of detection for several small organic molecules were in the sub-picomole range. Examination of competitive ionization revealed that signal suppression occurs only at high (mM) concentrations of competing substances.

12.
J Am Soc Mass Spectrom ; 28(2): 263-269, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27757823

ABSTRACT

The flowing atmospheric-pressure afterglow (FAPA) source was used for the mass-spectrometric analysis of vapor samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample vapor with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte vapor in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data. Graphical Abstract ᅟ.

13.
Appl Spectrosc ; 71(6): 1280-1288, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27872218

ABSTRACT

Glow discharges have long been used for depth profiling and bulk analysis of solid samples. In addition, over the past decade, several methods of obtaining lateral surface elemental distributions have been introduced, each with its own strengths and weaknesses. Challenges for each of these techniques are acceptable optical throughput and added instrumental complexity. Here, these problems are addressed with a tilting-filter instrument. A pulsed glow discharge is coupled to an optical system comprising an adjustable-angle tilting filter, collimating and imaging lenses, and a gated, intensified charge-coupled device (CCD) camera, which together provide surface elemental mapping of solid samples. The tilting-filter spectrometer is instrumentally simpler, produces less image distortion, and achieves higher optical throughput than a monochromator-based instrument, but has a much more limited tunable spectral range and poorer spectral resolution. As a result, the tilting-filter spectrometer is limited to single-element or two-element determinations, and only when the target spectral lines fall within an appropriate spectral range and can be spectrally discerned. Spectral interferences that result from heterogeneous impurities can be flagged and overcome by observing the spatially resolved signal response across the available tunable spectral range. The instrument has been characterized and evaluated for the spatially resolved analysis of glow-discharge emission from selected but representative samples.

14.
Appl Spectrosc ; 70(12): 1952-1964, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27940534

ABSTRACT

Over the last several decades, science has benefited tremendously by the implementation of digital electronic components for analytical instrumentation. A pioneer in this area of scientific inquiry was Howard Malmstadt. Frequently, such revolutions in scientific history can be viewed as a series of discoveries without a great deal of attention as to how mentorship shapes the careers and methodologies of those who made great strides forward for science. This paper focuses on the verifiable relationships of those who are connected through the academic tree of Malmstadt and how their experiences and the context of world events influenced their scientific pursuits. Particular attention is dedicated to the development of American chemistry departments and the critical role played by many of the individuals in the tree in this process.

15.
Talanta ; 102: 26-33, 2012 Dec 15.
Article in English | MEDLINE | ID: mdl-23182571

ABSTRACT

The solution-cathode glow discharge (SCGD) is an optical emission source for atomic spectrometry comprised of a moderate-power atmospheric-pressure DC glow discharge sustained directly upon the surface of an electrically conductive solution. The SCGD boasts a simple, inexpensive design and has demonstrated detection limits similar to those of more conventional excitation sources used in atomic spectrometry. Although the analytical performance of the SCGD as an optical emission source is well characterized, the mechanism through which the discharge atomizes and excites analyte from the sample solution remains a point of debate. The current paper presents visual observations of the SCGD from a variety of imaging techniques. The implications of the images regarding the mechanism of analyte solution-to-plasma transport and excitation in the SCGD are discussed.

16.
Environ Entomol ; 39(3): 798-810, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20550792

ABSTRACT

Studies that consider both biotic and abiotic determinants of organisms are rare, but critical to delineate underlying determinants of community richness (number of taxa) and abundance (number of larvae per water body). In this study, we consider the importance of disturbance (salinity) and predator and competitor variables on mosquitoes (Diptera: Culicidae) in small ephemeral water bodies across the Wheatbelt of Western Australia. Similar to mosquitoes, and contrary to general perceptions, nonculicid aquatic fauna (aquatic fauna) had a common occurrence (number or percentage of water bodies occupied) and were abundant (average density) in ephemeral water bodies, albeit with a simplified trophic structure. The occurrence and density (number per unit area) of aquatic fauna between water bodies were highly variable, but general relationships of aquatic fauna with rainfall, water body surface area, salinity, and mosquitoes were apparent. In contrast to mosquitoes, the density of aquatic fauna declined with recent rainfall, implying mosquitoes may colonize newly created water bodies more quickly than aquatic fauna. Assemblages (richness and density of taxa) of aquatic fauna changed along a salinity gradient, as did mosquitoes, and this was pronounced for predator groups. Densities of mosquitoes were not limited by any single taxonomic group, by a negative relationship. However, the density and richness of mosquitoes generally declined in association with increased richness of predators and density of all other taxa (taxa not specifically classified as predators or competitors of mosquitoes). These relationships may account for higher densities of mosquitoes in smaller water bodies, where richness of predators is reduced and the density of other taxa does not differ from larger water bodies. Our results also suggest salinity in the Western Australia Wheatbelt may facilitate greater abundance of halotolerant mosquitoes, Aedes alboannulatus Macquart and Aedes camptorhynchus Thomson (a vector of Ross River virus [Togoviridae: Alphavirus]), by releasing them from biotic regulation.


Subject(s)
Culicidae , Rain , Salinity , Wetlands , Animals , Coleoptera , Crustacea , Hemiptera , Western Australia
17.
Environ Entomol ; 38(6): 1585-94, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20021752

ABSTRACT

Environmental disturbance may have direct and indirect impacts on organisms. We studied the colonization of ephemeral water bodies by mosquitoes (Diptera: Culicidae) in the Wheatbelt region of southwest Western Australia, an area substantially affected by an expanding anthropogenic salinization. Mosquitoes frequently colonized ephemeral water bodies, responded positively to rainfall, and populated smaller water bodies more densely than larger water bodies. We found that the habitat characteristics of ephemeral water bodies changed in association with salinity. Consequently relationships between salinity and abundance of colonizing mosquitoes were direct (salinity-mosquito) and indirect (salinity-water body characteristics-mosquito). Overall, the structure of mosquito assemblages changed with increasing salinity, favoring an increased regional distribution and abundance of Aedes camptorhynchus Thomson (Diptera: Culicidae), a vector of Ross river virus (RRV; Togoviridae: Alphavirus). We conclude secondary salinization in the Western Australia Wheatbelt results in enhanced vectorial potential for RRV transmission.


Subject(s)
Aedes , Salinity , Wetlands , Animals , Insect Vectors , Rain , Ross River virus , Western Australia
18.
Vector Borne Zoonotic Dis ; 9(6): 611-22, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19326966

ABSTRACT

Alterations in transmission of vector-borne zoonoses are often linked to environmental change. However, ecological processes that determine variability in potential for transmission are generally not well understood. Ross River virus (RRV, Togoviridae: Alphavirus) is a mosquito-borne zoonosis in Australia with a significant human disease burden. The inland southwest (Wheatbelt) of Western Australia (WA) is substantially affected by an anthropogenic salinization of agricultural land (dryland salinity). Aedes camptorhynchus Thomson (Diptera: Culicidae) is the dominant vector of RRV in southwest WA and is halophilic. As such, dryland salinity may influence potential for RRV transmission by influencing interactions between Ae. camptorhynchus and mammalian hosts. We surveyed areas of the Wheatbelt with varying salinity impacts and found Ae. camptorhynchus was more abundant in saline areas, whereas sheep Ovis aries (Linnaeus 1758, Bovidae) declined with increasing salinity. We used a deterministic model to examine interactions between Ae. camptorhynchus and mammals, and we assessed potential for RRV transmission. We found variation in potential for RRV transmission was positively related to increasing salinity and abundance of Ae. camptorhynchus and negatively associated with increasing abundance of Macropus fuliginosus (Desmarest 1817, Macropodidae). Abundance of Ae. camptorhynchus determined more variation in potential for RRV transmission than other variables. Accordingly, dryland salinity increases the zoonotic potential for RRV transmission primarily by facilitating abundance of Ae. camptorhynchus. Human RRV notifications do not currently reflect the salinity-RRV transmission potential in the Wheatbelt but appear to be associated with RRV activity in the enzootic coastal zone. We speculate dryland salinity is a determinant of potential for RRV transmission but not activity. Dryland salinity is predicted to expand two- to four-fold by 2050. Preservation and restoration of freshwater ecosystems may ameliorate the potential for transmission of RRV and possibly incidence of human disease.


Subject(s)
Aedes/virology , Alphavirus Infections/veterinary , Environment , Insect Vectors/virology , Ross River virus , Salinity , Aedes/growth & development , Alphavirus Infections/transmission , Animals , Fresh Water , Humans , Insect Vectors/growth & development , Linear Models , Models, Biological , Population Dynamics , Western Australia , Zoonoses/transmission , Zoonoses/virology
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