Climate change alters vector ecology, affecting disease transmission dynamics. Temperature and precipitation changes impact the distribution, abundance, and behavior of vectors such as mosquitoes and ticks, influencing their survival, development, and reproduction, thus increasing the transmission rates of vector-borne diseases (24,25). A comprehensive review on the role of vector trait variation in vector-borne infection dynamics emphasized how traits such as biting rate, host preference, and longevity vary among individuals within vector populations (26). The study reviewed empirical evidence for variation in vector traits and their incorporation into mathematical models of vector-borne disease transmission, finding that traits such as biting rate, host preference, and longevity vary significantly across individual vectors and environmental conditions, impacting vector population dynamics and pathogen transmission rates (26). These variations, driven by genetic differences, phenotypic plasticity, and environmental factors such as temperature and humidity, result in non-linear effects on disease dynamics (26). The study emphasized that small variations within populations can have compounding effects on disease spread, with vectors exhibiting higher biting rates or longer lifespans disproportionately contributing to transmission (26).

Changing climate conditions expands the geographic range and habitats of disease vectors. Warmer temperatures and altered precipitation patterns enable vectors to thrive in new regions, increasing the spread of diseases such as malaria, dengue, and Lyme disease in areas previously free from these illnesses (27-29). Changes in temperature and precipitation can also influence vector behavior, including feeding patterns, host-seeking behavior, and flight activity. Warmer temperatures may prolong the active season for vectors, increasing their biting rates and the likelihood of human-vector contact (30). Additionally, altered rainfall patterns can impact vector breeding sites, leading to changes in vector abundance and distribution (2).

Long-term projections based on climate models suggest substantial shifts in the distribution and seasonality of vector-borne diseases under various greenhouse gas emission scenarios. For example, under high-emission scenarios [Representative Concentration Pathway (RCP)8.5], the geographic range of malaria vectors is projected to expand into higher elevations and temperate regions by mid-century, with transmission suitability increasing in East Africa and parts of South Asia (31). Similarly, Aedes aegypti and Aedes albopictus, vectors of dengue and Zika, are expected to expand their habitat globally, affecting an estimated additional 1 billion individuals by 2080, particularly in Europe and North America (32). By contrast, lower-emission pathways (RCP2.6) could limit these expansions significantly, underscoring the importance of climate mitigation efforts in disease prevention. These projections not only highlight future hotspots of disease transmission but also stress the need to integrate climate modeling into vector surveillance systems and maternal health strategies.

A study by Baafi and Hurford (33) developed a stage-structured model incorporating laboratory data to assess how temperature and rainfall impact Anopheles mosquitoes, revealing that seasonal weather conditions cause significant variations in mosquito abundance across different African regions. The study focused on four distinct regions: Ain Mahbel in Algeria, Cape Town in South Africa, Nairobi in Kenya, and Kumasi in Ghana. The findings indicated that warmer regions with higher rainfall, such as Kumasi, exhibit higher mosquito abundance year-round. By contrast, cooler regions such as Ain Mahbel and Cape Town experience more pronounced seasonal peaks in mosquito populations (33). The model emphasizes the importance of considering seasonality, as neglecting it could lead to substantial overestimation or underestimation of mosquito populations, with different regions showing varying patterns of abundance peaks occurring between one to four times a year (33).

Further research conducted in the Canadian Prairies explored the influence of weather variables, temperature, precipitation, and humidity, on mosquito population densities, specifically focusing on four common mosquito vector species (34). Over 2 years, researchers collected >265,000 mosquitoes from 17 sites in Manitoba, identifying species-specific responses to climatic factors. Aedes vexans preferred high humidity, moderate temperatures, and low precipitation, while Culex tarsalis favored higher temperatures and had variable responses to precipitation. Coquillettidia perturbans thrived in high humidity and elevated minimum temperatures, and Ochlerotatus dorsalis showed increased numbers with higher precipitation levels (34).

In Hainan Island, China, a study examined the spatial and temporal dynamics of mosquito populations, revealing significant variations in density and community structures across different habitats and seasons (35). Using Centers for Disease Control and Prevention (CDC) light traps and Biogents (BG) Sentinel traps, researchers collected over 88,000 mosquitoes from urban, suburban, and rural areas between January and December 2018. The study identified nine species from four genera, with Culex quinquefasciatus being the most dominant, followed by Armigeres subalbatus and Anopheles sinensis. The study found clear seasonal variations in mosquito populations, with peak densities varying among species and sites. Danzhou had the highest mosquito biodiversity, while Haikou had the lowest. It also highlighted the importance of using complementary trapping methods, as CDC light traps were more effective for capturing Anopheles and Armigeres species, whereas BG Sentinel traps were more effective for Aedes mosquitoes (35).

Medlock et al (36) noted a significant expansion in the geographical distribution of the tick Ixodes ricinus (I. ricinus) in northern Europe, particularly in Sweden and Norway, attributable to climate change. The milder winters and extended vegetation periods resulting from increased temperatures and reduced snow cover have facilitated earlier questing activity in ticks (36). These climatic changes have made previously unsuitable areas habitable, leading to a northward shift in tick populations. This expansion is closely linked to warmer winters, which prevent ground temperatures from dropping below critical levels, thus enhancing tick survival and extending the period during which ticks can be active and reproduce (36). Consequently, these climatic shifts have significantly influenced the distribution and density of I. ricinus in northern Europe, with substantial implications for public health and ecological balance (36).

The climate change impacts on vector ecology are summarized in Table I, while the global distribution of vector-borne diseases in the context of climate change is illustrated in Fig. 1.

Climate variability, including natural climate oscillations such as the El Niño Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), can also influence vector-borne infections transmission dynamics. These climate phenomena can affect temperature, precipitation, and atmospheric circulation patterns, leading to fluctuations in vector abundance and disease transmission rates. For example, during El Niño events, warmer and wetter conditions in some regions can create favorable breeding habitats for mosquitoes, increasing the risk of diseases such as dengue fever and ZIKV. Similarly, climate oscillations can influence the timing and intensity of seasonal outbreaks of vector-borne diseases. Changes in ENSO and NAO-related temperature and rainfall can have an impact on vector populations and the availability of favorable breeding grounds, which can cause changes in how diseases are spread (37-42).

Numerous studies have documented the impacts of climate change on vector-borne infectious diseases worldwide, highlighting the complex interactions between climate, ecology, and human health.

For instance, researchers have linked the expansion of Lyme disease transmission areas in the United States to climate change, as warmer temperatures and altered precipitation patterns create more favorable conditions for tick survival and reproduction (43). Another study investigated the impact of climate change on the distribution of Lyme disease, a tick-borne illness, in North America (44). Using climate and ecological models, the researchers projected changes in the range of the black-legged tick, the primary vector of Lyme disease, under different climate scenarios (44). The study concluded that warming temperatures could lead to the expansion of tick habitats and an increase in Lyme disease cases in previously unaffected regions (44).

Similarly, in tropical regions, climate change has been associated with the increased transmission of diseases such as malaria and dengue fever, with rising temperatures extending the active season for mosquito vectors and expanding their geographical range (32,45). In a study of the effects of climate change on malaria transmission in Africa, the researchers utilized climate models to project future changes in temperature and rainfall patterns and their potential impacts on the distribution of malaria vectors. Their findings suggested that rising temperatures could expand the geographic range of malaria transmission, posing significant challenges for malaria control efforts (46). Another study examined the relationship between climate variability and dengue fever transmission in Southeast Asia. The authors found that fluctuations in temperature and precipitation influenced the breeding habitats of Aedes mosquitoes, the vectors responsible for transmitting the dengue virus (43). Changes in climate patterns were associated with shifts in the timing and intensity of dengue outbreaks, highlighting the role of climate variability in shaping disease dynamics (47).

Shifts in temperature and precipitation, which alter the distribution of disease vectors and amplify transmission risks, have implicated climate change in the resurgence of vector-borne diseases such as Chagas disease in South America. More specifically, research conducted in 2015 examined the potential effects of climate change on Chagas disease transmission in South America (48). Their findings indicated that climate change could lead to shifts in the distribution of Chagas disease, with implications for disease surveillance and control strategies (48).

In addition, another study investigated the influence of climate variability on the transmission of the West Nile virus (WNV) in the United States. The authors analyzed climate data alongside mosquito and bird abundance to assess the drivers of WNV transmission dynamics. The study found that warmer temperatures and changes in precipitation patterns influenced mosquito breeding and WNV transmission, highlighting the role of climate variability in shaping the risk of WNV outbreaks (49).

This section thoroughly examined how climate change alters vector behaviors, habitats, and disease dynamics, emphasizing how these changes increase the risks of vector-borne diseases such as malaria and dengue. Key mechanisms such as temperature shifts and precipitation changes were presented with case studies and models. While this section provided compelling evidence, it lacked granularity in addressing region-specific impacts and long-term projections under varied climate scenarios. Future studies should explore localized data to enhance predictive modeling for better adaptation strategies.

The global distribution and incidence of vector-borne diseases among pregnant women have exhibited significant variations across regions and over time. In 2020, ~121.9 million pregnancies occurred in areas at risk of malaria transmission globally. The distribution of these pregnancies was as follows: 52.9 million in the WHO South-East Asia Region, 46.1 million in the African Region, 11.1 million in the Eastern Mediterranean Region, 6.7 million in the Americas Region, and 5.1 million in the Western Pacific Region. From 2007 to 2020, the incidence of pregnancies in areas of Plasmodium falciparum transmission decreased by 11.4% globally, despite an overall increase in the number of pregnancies in these regions (52).

Regarding dengue, the prevalence among pregnant women varies significantly by region. For example, a study conducted in Port Harcourt, Nigeria, found a seroprevalence of dengue IgG antibodies of only 2.1% among pregnant women. This contrasts sharply with higher prevalence rates in other regions, such as Malaysia, where a seroprevalence of 32.4% was reported among pregnant women (53).

Significant regional disparities exist in the burden of vector-borne diseases during pregnancy, largely reflecting differences in healthcare infrastructure, surveillance capacity, and environmental exposure. In sub-Saharan Africa, where over 10 million pregnancies occur annually in malaria-endemic areas, limited access to antenatal care and preventive tools such as insecticide-treated nets has been associated with high rates of placental malaria, stillbirth, and maternal mortality (54). By contrast, the 2015-2016 ZIKV outbreak in Brazil disproportionately affected the northeastern regions, where under-resourced health systems and delayed vector control responses contributed to elevated rates of congenital Zika syndrome, highlighting geographic inequalities even within a single country (51). Similarly, in Southeast Asia, recurrent dengue outbreaks in the densely populated urban slums of the Philippines and Thailand pose ongoing risks to pregnant women, exacerbated by poor sanitation, limited vector control, and insufficient maternal health services (55). These examples underscore the critical need for regionally tailored public health strategies that address both biological and structural vulnerabilities.

Urbanization exacerbates the risk of vector-borne diseases for pregnant women. Poor urban infrastructure, inadequate waste management, and overcrowding create environments conducive to vector breeding, thereby increasing the risk of diseases such as dengue and malaria (56). Both urban and rural settings present unique challenges, necessitating tailored public health interventions (56). The burden of vector-borne diseases is often higher in urban settings due to these environmental conditions. For instance, urban areas with poor infrastructure and large slum populations experience higher rates of diseases such as dengue, as urban residents are more susceptible due to their proximity to breeding sites and limited access to adequate healthcare (54). In Cameroon, research revealed that mosquito-borne diseases such as dengue and malaria were significantly influenced by urbanization, with urban areas experiencing a higher disease burden compared with rural areas (57).

Conversely, rural areas face different challenges. Limited access to healthcare, poor housing, and closer proximity to natural vector habitats such as forests and water bodies contribute to high incidence rates of vector-borne diseases. In these regions, diseases such as malaria remain a critical concern due to the abundance of mosquito breeding sites and insufficient vector control measures. Pregnant women in rural areas are particularly vulnerable due to these factors, which are compounded by inadequate healthcare infrastructure (1).

The evolution of vector-borne infectious diseases in urban and rural settings is influenced by environmental changes, migration patterns, and socioeconomic factors. Urbanization, if well-planned, can reduce transmission through improved infrastructure and healthcare access. However, unplanned urbanization can lead to increased disease burdens among urban populations. Addressing these issues requires tailored interventions that consider the unique circumstances of both rural and urban settings to effectively mitigate the impact on pregnant women (56).

Physiological and immunological changes during pregnancy, such as adaptations to tolerate the genetically distinct fetus, reduce the ability to combat infections, making pregnant women particularly vulnerable to vector-borne diseases. These changes include fewer lymphocytes such as CD4 and CD8, fewer cytotoxic T cells, and a shift from Th1 to Th2(57). Hormonal changes during pregnancy can elevate body temperature and alter the production of substances such as carbon dioxide, which renders pregnant women more attractive to biting insects such as mosquitoes. More specifically, progesterone is responsible for increasing body temperature by influencing the hypothalamus, and estrogen affects water and electrolyte balance by increasing renal sodium retention, which can lead to changes in blood volume and pressure (58,59). Furthermore, the expansion of the abdominal area can lead to changes in skin physiology, such as increased temperature and moisture, making the skin more attractive to biting insects (60). Pregnancy also restricts the use of certain medications due to potential risks to fetal health, complicating the management of vector-borne diseases during this period. The limited availability of safe therapeutic interventions during pregnancy makes disease management difficult (61).

Beyond physiological changes, a range of sociocultural and economic factors significantly heighten the vulnerability of pregnant women to vector-borne diseases, particularly in low- and middle-income countries. Women with limited access to education may lack critical knowledge about disease prevention strategies such as insecticide-treated net usage or early symptom recognition. Poor housing conditions, including inadequate sanitation and lack of protective barriers such as window screens, increase human-vector contact. Moreover, rural residency often corresponds with poor infrastructure, long distances to healthcare facilities, and inconsistent vector control programs, all of which impede timely diagnosis and treatment. Sex inequities may further constrain the autonomy of women in seeking care or participating in public health interventions, especially in patriarchal societies where health decisions are made by male household members (62). The intersection of poverty, social marginalization, and environmental exposure is particularly pronounced during extreme weather events, which disproportionately displace pregnant women and disrupt access to essential maternal services (51). These overlapping vulnerabilities underscore the need for intersectional, equity-based public health strategies tailored to the needs of at-risk pregnant populations.

The effects of vector-borne diseases on pregnancy can vary depending on the stage of pregnancy, the type of pathogen, how the pathogen interacts with the immune system, and specific host factors.

ZIKV can cause numerous maternal and fetal complications during pregnancy, with the risk of these complications estimated to range from 5 to 42% (63). Pregnant women infected with ZIKV may experience symptoms such as mild fever, arthralgia, myalgia, a maculopapular rash, pruritus, conjunctivitis or conjunctival hyperemia, and edema of the extremities, typically manifesting in the first trimester. Rarely, severe neurological complications might occur (64). A systematic review demonstrated that complications associated with maternal ZIKV infection include a broad range of fetal and neonatal neurological and ocular abnormalities, fetal intrauterine growth restriction, stillbirth, and perinatal death. Notably, eight studies identified microcephaly as the primary neurological consequence, with an incidence of ~1% among newborns of ZIKV-infected women in one study (21).

Malaria is one of the most common vector-borne infectious diseases among people living in the WHO African Region (54). Every year, 125 million women become pregnant in malaria-endemic areas (65). Pregnant women are three times more likely than non-pregnant women to experience severe illness due to malarial infection, with a mortality rate from severe disease approaching 50% (66). Women in their first pregnancy are most at risk (6). Pregnancy induces a state of immune modulation, necessary to tolerate the semi-allogeneic fetus, which involves a shift from a Th1 to a Th2 immune response, rendering pregnant women more susceptible to malaria and reducing their ability to effectively combat pathogens. This immune shift is more pronounced in first pregnancies as the maternal immune system encounters fetal antigens for the first time (67). Malaria infection in pregnancy is known to cause high rates of spontaneous abortion, preterm delivery, fetal intrauterine growth restriction, stillbirth, congenital infection, and neonatal mortality, contributing to an estimated 10,000 maternal deaths annually (68).

Dengue fever infects an estimated 390 million individuals annually (69). It is a life-threatening illness with symptoms including fever, joint pain, myalgia, and cough in mild cases. Severe symptoms include dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), the latter having a high mortality rate and requiring urgent medical treatment. Dengue appears to be more severe in pregnant women than in the general population. One study found that the risk of DHF/DSS increased 3.4 times during pregnancy and was higher in the third trimester. The overall death rate in this study was 7.4% (70). Complications such as hypertension, emergency caesarean sections due to fetal distress, obstetric hemorrhage, pre-eclampsia, and eclampsia have been reported (55). A systematic review and meta-analysis reported that preterm birth and low birth weight were also common adverse pregnancy outcomes following dengue infection (71).

Lyme disease, transmitted by ticks, also poses serious risks during pregnancy. If untreated, it can lead to serious complications such as infection of the placenta, congenital heart defects, and stillbirth. However, with appropriate antibiotic treatment, these risks can be mitigated, and there is no increased risk of adverse birth outcomes (72). Early symptoms of Lyme disease, such as a bull's-eye rash, fatigue, and muscle aches, can occur within a month of being bitten by an infected tick. It is crucial for pregnant women who suspect they have been bitten to seek immediate medical attention to start treatment early and prevent complications. The standard treatment for Lyme disease during pregnancy involves antibiotics such as amoxicillin, as doxycycline is generally avoided due to its potential adverse effects on the fetus (73). Research on the long-term effects of Lyme disease on pregnancy and infant development is ongoing. A pilot study by Children's National Hospital (Washington, USA) aims to assess the neurodevelopmental impacts of utero exposure to Lyme disease, highlighting the need for further investigation into this under-researched area (74).

This section highlighted the amplified risks of vector-borne diseases during pregnancy, including adverse outcomes such as miscarriage, preterm birth, and congenital anomalies. It integrated physiological vulnerabilities of pregnant women and the effects of disease-specific pathogens such as Zika and malaria. The discussion is limited in addressing how sociocultural and economic factors exacerbate these risks, particularly in low-resource settings. Further research should investigate how intersecting vulnerabilities influence outcomes and how tailored public health interventions can be developed.

Malaria, ZIKV, and dengue fever significantly impact pregnancy outcomes, particularly in endemic regions, where they increase the risk of complications such as miscarriage, stillbirth, preterm birth, and congenital abnormalities (87). Public health strategies emphasize controlling vectors through measures such as the use of insecticide-treated nets, indoor residual spraying, and environmental management practices aimed at reducing mosquito breeding grounds (88). These measures are part of community-wide efforts not only to protect pregnant women but also to control disease transmission. Furthermore, health education is vital for informing pregnant women and healthcare providers about the risks and preventive measures associated with these diseases. Educational campaigns and provider training enhance community engagement, improve preventive practices, and ensure pregnant women have access to necessary prenatal care (89,90).

Effective prevention of vector-borne diseases in pregnant women requires multi-faceted policy initiatives that support vector control programs, healthcare access, and the strengthening of healthcare systems. This involves allocating funds for mosquito control, improving infrastructure for vector surveillance, and ensuring that pregnant women have access to comprehensive antenatal services. These services should include screenings and appropriate treatments for vector-borne diseases (91). Additionally, there is a strong emphasis on supporting research and development of targeted interventions such as vaccines, which are crucial for long-term prevention efforts (5,71).

Through enhanced surveillance and capacity building, healthcare systems must adapt to the changing epidemiology of vector-borne diseases due to climate change. Advanced data collection and analysis methods are necessary to detect shifts in disease patterns and vector distribution (3). Training for healthcare professionals is essential to recognize symptoms of emerging diseases and implement effective diagnostic and management protocols (92). Furthermore, integrating vector control and disease prevention into climate change adaptation strategies is crucial. Public health campaigns should raise awareness about the risks posed by a warming climate and promote preventive behaviors (93).

Several successful case studies demonstrate how targeted interventions can effectively reduce the burden of vector-borne diseases among vulnerable populations, including pregnant women. In Sri Lanka, a sustained, multi-decade malaria elimination program combined indoor residual spraying, bed net distribution, and decentralized disease surveillance, resulting in zero indigenous cases since 2012 and WHO certification of malaria-free status in 2016(94). Similarly, the response of Brazil to the Zika outbreak incorporated real-time birth surveillance for microcephaly, integrated mosquito control efforts, and rapid prenatal screening in high-risk regions, which helped mitigate congenital Zika syndrome incidence during subsequent waves (95). In Vietnam, community-led dengue control campaigns focused on environmental management and water container cleaning reduced larval indices and dengue cases by over 50% in targeted provinces (96). These examples underscore the importance of integrated, context-sensitive approaches that combine public health infrastructure, community engagement, and sustained funding.

Future research should prioritize understanding how climate change influences the transmission of vector-borne infectious diseases during pregnancy and assessing the long-term effects on maternal and neonatal health. Innovative surveillance tools and predictive modeling are needed to monitor these changes effectively (62,92). Longitudinal studies tracking the impact of vector-borne diseases on pregnancy outcomes can inform clinical guidelines and improve intervention strategies (93,97). Additionally, interdisciplinary collaboration among public health workers, midwives, and environmental health professionals is crucial for developing evidence-based strategies that address the interplay of environmental, social, and biological factors affecting pregnant women and their babies in the context of climate change (1,98). The public health strategies to mitigate the impact of vector-borne diseases on pregnant women is summarized in Table II. In addition, how climate change affects various infectious diseases and their specific impacts on pregnant women are presented in Table III. This section focused on actionable strategies such as vector control measures, surveillance systems, and antenatal care interventions. It underscored the importance of integrating climate adaptation into public health policies. While it presented numerous strategies, the lack of real-world case studies and quantitative evidence supporting the effectiveness of these measures is a limitation. Expanding the discussion with data-backed examples would strengthen the practical utility of the recommendations.

Comprehensive public health strategies to mitigate vector-borne diseases during pregnancy are illustrated in Fig. 3.