Ethnic Conict as a Risk Amplier for Resurgent P. Vivax Malaria in Temperate Zones: A Case Study from the Caucasus Region.

Background: One of the most protracted post-Soviet conicts of the 1990s was a territorial dispute between Armenia and Azerbaijan over the contested Karabakh region. Years of ethnic violence led to the displacement of nearly a million refugees, as well as a public health crisis that included epidemics of malaria, diphtheria and other preventable diseases. Malaria is not usually considered a health risk in temperate climates, but seasonal epidemics were widespread throughout the Caucasus in the early decades of the twentieth century. Methods: This paper combines qualitative historical research with geospatial analysis to explore how endemic malaria was controlled during the Soviet era, and how ethnic conict recongured local ecologies to facilitate the re-emergence of P. vivax after the Soviet collapse in the 1990s. Results: This research reveals that ethnic conicts have specic qualities that increase risks of infectious and vector borne disease outbreaks, even in places that have successfully achieved a modern health and mortality prole. The risk ampliers of ethnic conicts include 1) the creation of contested spaces controlled by separatists that are outside of any national public health surveillance system; 2) mass population movements and refugee outows due to ethnic violence; and 3) changes in land use that expand potential mosquito breeding sites throughout the conict zone. Conclusions: Ongoing hostilities between Armenia and Azerbaijan, combined with the repopulation of key vector species (specically An. sacharovi) lead us to conclude that contemporary populations in the Caucasus remain vulnerable to resurgent outbreaks of ethno-nationalist violence as well as the return of seasonal malaria, even after decades of successful control. by ethnic warfare or other conicts between non-state actors.


Introduction
Malaria is considered a tropical disease, but there is also a temperate or seasonal variety that can create signi cant population morbidity (1,2,3,4,5,6). Epidemics of P. vivax coincided with planting and harvest seasons in the Caucasus in the early decades of the twentieth century, and these outbreaks incapacitated rural populations in ways that limited agricultural and industrial development (7). In 1924, health o cials described seasonal malaria in the Caucasus as a "veritable scourge" that a icted "up to eighty percent of the population" in the spring and fall (8).
An ambitious series of malaria control projects were undertaken by Soviet o cials working together with the League of Nations and o cers from the United States Public Health Service in the 1920s and 1930s. These involved large scale engineering projects as well as authoritarian vector control enforced at the community level. The social environment was also targeted for aggressive engineering to reduce the potential for internal con ict, and to integrate rural ethnic populations into the centralized Soviet system (9,10). Taken together, these activities were successful in controlling seasonal malaria in the Caucasus for the remainder of the Soviet era (4,11).
The collapse of the Soviet Union, however, reversed decades of public health success in just a few short years (12,13,14,15). In the Caucasus region, these public health crises emerged in the context of ethnic con ict. These con icts developed in the late 1980s and early 1990s, but should be considered examples of a contemporary variant of warfare: protracted con icts between non-state actors, often fueled by ethnic violence and nanced in part through environmental resource exploitation in the informal economy (16,17,18,19,20). When left unchecked, these kinds of con icts appear capable of reversing long standing public health successes and generating sustained epidemics of preventable infectious diseases. In the Caucasus these reversals were evident in the resurgence of seasonal malaria, along with parallel outbreaks of diphtheria, tuberculosis, measles, and viral hepatitis, all compounded by widespread nutritional stress, energy crisis and food insecurity (21).
Con ict-driven public health crises that emerge on the margins of failing or fragile states have been described by many researchers but are not fully theorized in the eld of global health (22,23,24,25), and European examples are rare. Many core textbooks and teaching materials remain in uenced by twentieth century modernization theory and mortality transition theory, which assume that geopolitical boundaries are fundamentally stable, and that countries that have achieved a modern mortality pro le are not likely to see dramatic reversals to pre-modern health conditions (26,27). There is not a robust vocabulary to explain the kinds of health crises that develop in regions fractured by ethnic con ict or in the aftermath of political collapse. This paper presents a longitudinal case study of malaria control in the Caucasus through the con ict years of the 1990s with the goal of exploring how public health crises emerge and expand in regions destabilized by ethnic warfare or other con icts between non-state actors.

Research And Research Methods
The Karabakh con ict developed in the late 1980s and remains unresolved. Hostilities were frozen by a cease re agreement in the mid 1990s, but skirmishes have continued to erupt in border areas and access to the region is limited (28,29). For these reasons, this project developed multiple indirect methods for researching the resurgence of epidemic malaria. These include qualitative research in historical document collections and analysis of remote sensing data.
These indirect methods were supplemented with a small number of informal interviews with regional specialists, public health professionals, environmental scientists, journalists, plus a review of secondary sources. A site visit was undertaken to Armenia in the summer of 2018, and several additional interviews were conducted with environmental health professionals in various government ministries. The geospatial analysis included development of speci c methods to detect changes in surface water, agriculture and overall land use patterns (30). We also mapped the historical malaria occurrences in Russia and the Caucasus for 1922 and for the con ict and post-con ict period between 1991 and 2003. In addition, we calculated the topographic wetness index as an indicator of environmental wetness which is associated with increased habitat for malarial mosquitoes.

Environmental Dynamics of P. vivax Malaria
Malaria is not a single disease, but a diverse group of blood parasites with different evolutionary lineages, variable mammalian hosts and multiple species of mosquito vector (1). P. falciparum or tropical malaria produces the most severe pathology in humans and is responsible for the majority of global deaths. P. vivax, on the other hand, is a seasonal variant that remains dormant in human hosts during winter months, then re-emerges in transmissible form when mosquitos re-appear in the spring (6). While seasonal malaria is rarely fatal, it can produce signi cant population morbidity, especially in agricultural communities or immunologically naive populations (31). P. vivax is also the most globally prevalent form of malaria, with approximately 2.5 billion individuals at risk worldwide (32). There are potentially serious health complications, including anemia, jaundice and immune system dysfunction (33,34). Second order effects of widespread P. vivax infection include regional food shortages, poverty, economic burdens and delayed cognitive development in children (35). There is currently no vaccine against any form of malaria, and drug treatments for P. vivax can be complicated by ancestral genetic adaptations such as G6PD de ciency (1,33). Transmission dynamics, patterns of host immunity, and parasite life cycle variations of P. vivax are still not fully understood, and for these reasons some researchers have described P. vivax as a "neglected tropical disease of major global importance" (36).

Twentieth Century Modernization And Soviet Malaria Control
The Soviet Union consolidated its territorial control of the Caucasus republics during the 1920s.
At that time, malaria was prevalent throughout the region, and co-circulation of P. vivax and P. falciparum created large overlapping epidemics that severely constrained Soviet colonization and industrial development programs. Debilitating malaria outbreaks among Russian troops entering the Caucasus from northern latitudes made it di cult for Soviet authorities to consolidate territorial control. In 1923 one public health report estimated approximately 680,929 cases of malaria throughout the USSR, and these were considered to represent only about one fth of the total cases The most severe malaria outbreaks in the Soviet Union were concentrated in river basins that drained the mountainous Caucasus region. The Bashkir region of the USSR, for instance, was estimated to have over ve thousand cases of malaria per 100,000 inhabitants in 1923, up from 2529 cases per 100,000 in 1922. In the lower Caucasus, there were estimated to be over one million cases of malaria in 1923, with most going untreated due to shortages of quinine. In Armenia, malaria was described as the "most important communicable disease," in the 1920s, comprising approximately fty percent of the total infectious disease burden.
In keeping with the assumptions of twentieth century mortality transition theory, malaria and other preventable infectious diseases were viewed as relics of the pre-modern past by public health professionals working in the 1920s and 1930s (37,38). Soviet, North American and European health authorities embraced variants of this progressivism and committed signi cant resources to collaborative state-sponsored public health work in the rst half of the twentieth century. Diseases associated with rural poverty were viewed as impeding human progress, and speci cally targeted for aggressive eradication efforts. As malariologist L. W. Hackett stated in the 1930s, "The consensus of opinion was that this disease [malaria], like typhus and plague, was an anachronism among advanced people in modern times and would soon cease to be of importance in the temperate zone" (39).
The convergence of public health planning goals between the United States, Europe and the Soviet Union led to a series of collaborative programs in the decades preceding the Cold War. The Epidemic Commission of the League of Nations was formed in 1920 and combined public health expertise from member nations to eliminate diseases associated with poverty. In 1923 a subgroup of six malariologists developed an internal working group that later became known as the League of Nations Malaria Commission. In 1928 this group sponsored a tour of successful malaria control programs in the southern United States so that environmental engineers and vector control specialists in other countries could apply these techniques to malarious regions in Europe and the Soviet Union. By 1933 the group included over fty experts from various elds, who shared epidemiological reports and collaborated in clinical research and drug trials to document successful eradication and control techniques.
O cials in the USSR also developed uniquely Soviet methods to expand rural health initiatives. State enterprises, for instance, were required to develop plans for mosquito eradication and to control mosquito breeding at construction sites (40). From 1946-1951, a DDT spraying campaign extended over nearly 200 million square kilometers in the USSR. The centralized Soviet medical system was also able to deploy teams of specialists (including etymologists, doctors, nurses and hydro-technicians) to work in malarious regions, and these capabilities also contributed to overall reduction in malaria prevalence. According to one researcher, overall malaria rates declined from 43.1 per 10,000 in 1950 to 9.8 per 10,000 in 1952 (40).
Much of this anti-malaria work coincided with the growing centralization of political power by Joseph Stalin and increasing censorship of negative health data in the USSR. By the early 1930s, Soviet health o cials were under great pressure to report progress consistent with the goals outlined in the rst and second Five Year Plans. These pressures could be extreme: doctors who diagnosed patients with typhus after Stalin declared the disease eradicated were arrested and accused of spreading anti-Soviet propaganda (41). All Soviet health data from the Stalin era and beyond should be viewed with caution, so it is di cult to pinpoint exactly when malaria began to recede from the Caucasus. But later research suggests major declines during the 1940s and 1950s (42,40). Malaria was formally declared eradicated in Armenia in 1963 (43).

Ethnic Groups And Political Boundaries In The Ussr
In the 1920s and 1930s, Soviet social engineers were also eager to transform the "backward" cultural terrain of the Caucasus from a clan-based, rural, religious peasantry into a modern, secular Soviet outpost. Soviet social theory was explicitly evolutionist and ethnic identity was understood to represent an archaic or "pre-Soviet" stage of human social development (44,10,20). As a result, overt representations of ethnic identity in the Caucasus (including religious practice, traditional clan kinship systems, land tenure, inheritance customs, languages and traditional dress) were restricted or recon gured by Soviet authorities. The result of these trends was an authoritarian recon guration of the social order that included the elimination of traditional ethnic territorial divisions and the creation of new administrative boundaries under the central authority of the USSR. According to one scholar, Soviet governance was originally welcomed by residents of the region, as it promised a respite from longstanding ethnic violence (45).
Three levels of ethnopolitical governance were established for the Caucasus by the USSR: 1) Soviet Socialist Republics (SSR), which were considered semi-sovereign countries in theory if not in practice; 2) Autonomous Republics (ASSR), which were considered "national states" without individual sovereignty and held more tightly under the control of Moscow, and 3) Autonomous oblasts (AO), which were located within larger Soviet states but granted some level of local governance (20). Some of these units were more ethnically homogenous than others, but all included multiple ethnic groups forced into an uneasy coexistence under the threat of Soviet military repression.
Many of these Soviet administrative territories changed over time, with phases of consolidation accompanied by cycles of "cruel repressions" (10).
But they were all fundamentally arti cial and designed to weaken ancestral ethnic a liations. The stubborn persistence of ethnicity in the region eventually led to more violent forms of repression. By the middle of the Stalin era, the USSR resorted to wholesale deportation of ethnic groups viewed as anti-Soviet. Thousands of Chechens, Tatars, Kalmyks, Balkars, Ingush and others were expelled from the Caucasus and relocated to sparsely populated areas of Central Asia in the 1940s (46,47,9,20). By the early 1950s, a total of 3.5 million Soviet citizens had been forcefully removed from their ancestral homelands (17).
According to one historian, over twenty percent of exiled Chechens and Ingush died during the rst four years of exile in Central Asia (48). The same pattern was repeated with exiled Crimean Tatars in 1944, with over 70,000 of 190,000 deportees dying en route due to poor health and sanitation conditions in transport trains. Other ethnic groups were spared physical dislocation but subjected to "ethnocide" or cultural erasure "because they were seen as too small and irrational" to t into Stalin's idea of a modernizing Soviet state (48).
Armenia was the most ethnically homogenous Soviet SSR, with Armenians constituting over ninety percent of the population (20). This demographic pattern contributed to a stronger fusion of ethnicity with national identity in Armenia than in other areas of the Caucasus. Armenian nationalism was further bolstered by historical trauma of the Armenian genocide in the early twentieth century, when over one million Armenians were killed or driven out of the Ottoman Empire (20). In neighboring Georgia (also an SSR), by contrast, the population was approximately seventy percent ethnic Georgians, with signi cant minority groups of Dagestanis, Ossetians, Abkhazians, Azeris, and others. Azerbaijan, on the other hand, was approximately eighty percent Azeri with subgroups of Dagestanis, Tatars, Lezgins, Kurds and Turks (20).

Ethnic Con ict And Soviet Collapse, 1988-1994
The Nagorno-Karabakh region extends as a long corridor between Armenia and Azerbaijan. This area was historically populated by ethnic Armenians but placed under the control of the Azerbaijan SSR by Soviet authorities as a way to weaken Armenian nationalism. This led to repeated petitions by Armenian o cials for reuni cation. But appeals to ethnonationalism were suppressed by Soviet authorities in the 1960s and 1970s. In the 1980s, however, Soviet Premier Gorbachev signaled his intentions to reduce political repression in Soviet society though the twin programs of Glasnost and Perestroika. These policy shifts coincided with an administrative decision by Soviet authorities to transfer land from an Armenian kolkhoz in Karabakh to one under Azeri control.
These developments increased tensions in the region at a time when Soviet authorities were less inclined to suppress dissent. Outbreaks of ethnic violence were reported in Karabakh around this time, though speci c details are lacking in available historical records. According to one analyst, ethnic militias began to form in 1988 and engaged in rounds of reciprocal ethnic cleansing in several Karabakh villages. These militia groups were not professional soldiers but were described as rural populations armed with little more than "improvised weapons" (49). One scholar has estimated that before 1990, the total number of combatants on each side in the Karabakh con ict was only around two hundred (20), and many were composed of extended families rather than professional soldiers (50).
Reports of ethnic violence in Karabakh reverberated in urban areas and triggered painful cultural memories of past con icts and historical grievances. According to one group of researchers, Armenians in the Karabakh region had experienced decades of abuse at the hands of the Azeri government during the Soviet period. "Resources for economic development have been withheld or diverted elsewhere…and Armenian cultural and educational facilities in the [Karabakh] province have been systematically underfunded and restricted" (51). The Armenian genocide of the early 20th century also created a lasting cultural trauma that generated "a mass trauma" that in turn led to mass mobilization of violence during the Soviet collapse (52).
In February 1988, twenty-six Armenians were killed in the Azeri town of Sumgait, leading over a million people to gather in protest in Yerevan. This Armenians' and Azerbaijanis' movement for de-colonization from Moscow" (53). New waves of persecuted Armenians ed Azerbaijan, with over 180,000 arriving in the rst half of 1989. Over 160,000 Azeris were correspondingly displaced from Armenia during this time (50). Militia groups in Karabakh expanded and allegedly hardened their tactics against one another.
In January 1990, the Soviet government made a nal attempt to suppress separatism and ethnic fragmentation in Karabakh, and troops were sent to Baku. Hundreds of thousands of protestors marched against this new wave of repression, as well as against ethnic violence. Armenians in Baku were targeted in these demonstrations, though it is unclear by whether by Soviet troops, Azeri civilians or both. Hundreds of protestors were arrested or killed, intensifying the regional push for independence (20). Similar events were unfolding in neighboring Georgia, with separatist violence erupting between various minority groups, as well as with Soviet authorities (9,20).
By the summer months, the Armenian national movement effectively ended Soviet rule in Armenia. Soviet forces continued to support Azeri leadership and worked to punish Armenian nationalists and disarm militias in the Karabakh region. An economic blockade was put in place to cut off energy supplies to Armenia, further escalating tensions. New waves of ethnic violence and displacement occurred through 1991, with Armenians deported from villages in Karabakh and their property and agricultural lands redistributed to Azeri refugees (50). Armenian militias in Karabakh gained additional support from the newly established Armenian government and began to retaliatory raids against Azeri settlements.
The Soviet Union underwent its nal collapse in the summer of 1991, though informal reports suggest that Soviet troops stationed in the Caucasus were "self-privatizing" or selling their services and weapons to local militias in the late 1980s (50). This further destabilized the Karabakh region and left ethnic militias to function as the default security agencies, now armed with sophisticated Soviet military weapons. The con ict intensi ed into a "full-edged if undeclared war" fueled by an aggressive spirit of ethnonationalism. As with other post-Soviet con icts there were also "violent entrepreneurs" who had been active in the informal economy of the USSR and sought to pro t from the hostilities (53,50,54,55).
The Karabakh con ict was one of over twenty ethno-territorial con icts that ared up in the Caucasus region in the 1990s. Seven of these expanded into actual wars with widespread violence (56,54). During this time, Russia itself was also destabilized by internal con icts between rival organized crime groups. Homicide rates soared as criminal gangs-many with ties to the KGB and other security services-fought one another for market share of newly privatized industries (57,58,59) From 1992-1994 the Karabakh region endured repeated cycles of bombing, ethnic violence, looting, and attacks on civilians. By the time a cease re was enacted in 1994, over 350,000 people had been expelled from their homes, and agricultural production, transportation and basic institutions of commerce were severely disrupted or destroyed (60,53). Approximately 200,000 Azerbaijanis ed Armenia in the rst phase of con ict (1988)(1989), and another 500,000 left the Karabakh region during the peak con ict years of 1992-1994, leaving Azerbaijan with one of the highest rates of displaced people in the world (53). A similar number of Armenians were also displaced, and Azerbaijan ultimately lost about twenty percent of its pre-war territory (20). An estimated 30,000 people died in the hostilities with thousands more suffering "untold misery" from disease, impoverishment, displacement, cold, hunger and looting (50).

Epidemic Malaria And Ethnic Con ict
The exact origin of the malaria epidemic that struck Armenia and Azerbaijan in the 1990s remains unclear. There were reports of soldiers from Afghanistan and Chechnya ghting in the region, and speculation that these individuals could have imported malaria into the con ict zones (47; 50). Cases of locally acquired P. vivax were only recognized in Armenia after the cease re agreement in 1994. At that time, the Armenian Ministry of Health received assistance from the U.S. Centers for Disease Control and the World Health Organization to re-establish malaria control measures (42,61). According to one Armenian researcher, over 90% of the documented cases of P. vivax were found in refugees from the Karabakh region (42). The epidemic in Armenia continued to expand, with over one thousand total cases reported in 1998, about half of which were locally acquired.
A retrospective analysis by Azeri researchers indicates a peak in malaria transmission in Azerbaijan in 1996, with over thirteen thousand cases recorded, and a gradual decline lasting through the remainder of the 1990s, with full elimination achieved in the early 2000s (4).
The epidemic spilled over into neighboring Georgia, which reported hundreds of cases in the early 2000s after years of internal con ict (4,20).
Researchers have acknowledged these case counts are likely to be underestimates, due to pervasive instability and chaos. Neither analysis, however, examines the Karabakh epidemic in the context of systemic Soviet collapse and the expansion of ethnic territorial con ict. Instead, the uncertain status of the Karabakh region remains embedded in public health scholarship, with Azeri researchers describing the region as "occupied territories," (4), and Armenian researchers naturalizing the reincorporation of Karabakh into the political geography of Armenia (42).

Results
This case study presents a historical and spatial analysis of the resurgence of P. vivax malaria in the southern Caucasus region during the armed con ict between Armenia and Azerbaijan. The historical documents reveal an important insight: controlling epidemic malaria in the Caucasus in the 1920s and 1930s required decades of authoritarian recon guration of the social environment and suppression of ethnic identity, as well as large scale efforts to re-engineer the physical environment through improved drainage and mosquito control. Conversely, the armed con ict that erupted in the late 1980s changed the social and physical environment very quickly, so that malaria was able to re-emerge in epidemic form by the time of the cease re agreement in 1994.
Closer examination of the armed con ict itself reveals the importance of informal ethnic militias in this process of environmental recon guration.
Ethnic militias operate differently than regular state-sponsored armed groups, and these differences have important insights for population health.
Irregular armed groups, for instance, operate outside the control of established nation-states and often rely on activities in the informal economy for nancing. In the Caucasus these activities included illegal logging, smuggling and destruction of properties owned by ethnic rivals (54,56). These activities took place in an ungoverned space created by the collapse of the USSR and the recon guration of national political boundaries. Separatist spaces by de nition have no public health surveillance systems so that infectious and vector borne diseases can circulate invisibly for some time.
Ethnic violence in the Caucasus con ict also led to massive population displacement with millions of refugees owing out of the con ict zone and into more stable regions of Armenia and Azerbaijan. These population ows effectively moved malaria, diphtheria and other infectious diseases out of Karabakh and into major metropolitan areas. The combination of depopulation and territorial uncertainty led to high rates of abandoned farmland in Karabakh, and these changes in land use further expanded mosquito breeding sites in the area.

Discussion
Researchers who study political collapse have noted that the process of state failure often begins with territorial contraction or "loss of control over political and economic space" on the part of the national government (62). Contraction of political boundaries accelerates the process of state failure, as peripheral regions establish their own informal governance systems under the control of non-state actors. Over time, the national government loses legitimacy as the state can no longer claim a monopoly on violence due to the fragmentation of cartographic space (63,64,65).
In the case of many post-Soviet con icts in the Caucasus and elsewhere, there was a return to "pre-modern" forms of social and economic life, and a rejection of the secular multiculturalism and bureaucratic administration that de ned modern Soviet society.
One Russian social scientist used the term "demodernization" to describe the social effects of armed con ict in Chechnya and other post-Soviet states (66). These pre-modern conditions developed in part due to the exodus of intellectuals and professionals from con ict zones, depriving society of, "those people capable of implementing the agenda of modern life through society's key institutional structures-such as economic and political administration, education and culture and social security" (66). Tishkov goes on to state that people who remained con ict zones experienced rapid transformation of the social and natural world, with kinship re-emerging as a dominant force of social organization, and non-state violence used to enforce or enhance traditional rules and norms. In this context, ethnic identity and religious practice emerged as expansive forces of social solidarity.
Tishkov has also described demodernization as "di cult to escape" once it has taken hold in a region (66). This variant of warfare is not constrained by the rules of combat that prevail between nation-state armies. Instead these armed groups blur lines between combatants and civilians, and often attack core institutions of modern life in the built environment, including schools, clinics and hospitals (54,66). In the Chechen con ict, for instance, civilian casualties "exceeded those of both Russia's army and the insurgents' battalions and guerrillas" (66). The homicide rate in Chechnya also increased by seven hundred percent between 1991-1993, signifying an overall breakdown in security and a return of ancestral clan-based systems that mobilize entire kin groups in cycles of retaliatory attacks (66).
The Karabakh con ict did not generate the same level of protracted internal violence as the con ict in Chechnya. But there are some important similarities. The early ethnic militias that developed in the late 1980s and early 1990s were funded in part by natural resource extraction that disrupted agricultural activities and led to signi cant loss of forest cover. Remote sensing analysis of land use patterns in the Karabakh con ict zone, for instance, reveal over sixty percent of agricultural lands were abandoned within a short period of time, indicating a massive "socioeconomic shock" (60). Abandoned agricultural lands are likely to increase mosquito breeding sites as irrigation systems are not maintained and stagnant pools of water can result. A group of entomological researchers has also described signi cant repopulation of A. sacharovi (a key mosquito vector for P. vivax) in parts of Armenia since the 1990s (68).
Spatial imaging also reveals high rates of forest disturbance in parts of the con ict area (60). There are anecdotal reports that several of the early militias in the Karabakh region nanced their insurgencies by exploiting timber resources, and in some areas forest disturbance rates reached almost twenty percent (60). Refugees and other impoverished populations in Armenia were known to have harvested timber in rural and urban areas to burn for heat following an energy blockade imposed by Azerbaijan in 1991 (69,70). These environmental disruptions were exacerbated by militia attacks on schools, hospitals and homesteads during the con ict, accelerating the exodus of refugees from the region (71).
Outbreaks of measles and diphtheria that emerged in Armenia during the con ict were successfully controlled by a vaccination campaign facilitated by international aid and humanitarian assistance agencies. Malaria control, however, is more complex. There is no vaccine for malaria, and successful prevention requires a complex array of activities that require a stable government with full territorial control, signi cant economic resources and strong political will-in other words, a modern nation-state. These conditions were irregular and uneven in the post con ict period, when both Armenia and Azerbaijan were fragile new states struggling to establish national governments following the cease re agreement in 1994.
Over time, Armenia and Azerbaijan did re-establish themselves as formal nation-states after the cease re agreement. Their new national governments then received assistance from the World Health Organization along with several NGOs to re-establish disease surveillance, improve drainage, rebuild irrigation systems and renew mosquito spraying. By the early 2000s, political administration and public health infrastructure were developed enough to control malaria once again. Armenia declared itself malaria free in the early 2000s (61), and Azerbaijan in the mid 2010s (74).
But the territorial status of Karabakh is still unresolved, and the potential for new outbreaks of ethnic violence remains high. In the spring and summer of 2020, at least sixteen people were killed in border skirmishes around Karabakh, sparking large public demonstrations and calls for retaliatory attacks. Armenia and Azerbaijan have continued to build up forces around the Karabakh region, and now have armies of drones capable of destroying one another's vital infrastructure, including water and power systems. In June 2020 the Azerbaijani Defense Minister even threatened to attack an Armenian nuclear power station in order to create a "Chernobyl type catastrophe" (75). In September 2020, hostilities broke out again with one news agency reporting " erce ghting" across the region (76).
These ongoing tensions suggest that Armenia and Azerbaijan remain vulnerable to new outbreaks of armed con ict and re-emergence of P. vivax malaria. According to our newly constructed topographic wetness index (see Fig. 5), for instance, many areas of Azerbaijan remain suitable for mosquito breeding based on analysis of yearly rainfall and surface water accumulation. Many Karabakh villages are still underpopulated and a good deal of farmland remains uncultivated. Any future interruptions in disease surveillance or vector control activities in the region are likely to create new opportunities for P. vivax to become re-established in the region.

Conclusions
This case study highlights the way ethnic con ict generated resurgent epidemics of preventable infectious and vector borne disease in the southern Caucasus region in the 1990s.
Our analysis has shown how ethnic separatist movements are different from other kinds of con icts. Separatists, for instance, seek to create semiautonomous zones or new states carved out of existing geography of an established nation-state. These con icts weaken the central government and create territorial blind spots for public health surveillance. The re-introduction of P. vivax malaria in the contested Karabakh region originally went unrecognized due to the interruption of vector control and disease surveillance that occurred during the Soviet collapse. As the con ict intensi ed, dispossessed refugees from the Karabakh con ict zone spread malaria into the more stable regions of Armenia and Azerbaijan, where it persisted for years before it was nally controlled.
The Karabakh con ict itself was frozen by a cease re agreement in 1994, and since that time the region has remained underpopulated. The uncertain status of Karabakh has led to abandonment of farmland and increased surface water accumulation-trends that have created expansive new habitat for Anopheles mosquitos. These environmental changes, coupled with unresolved nature of the con ict itself, suggest that the health crises of the 1990s could re-emerge in the 2020s. Furthermore, the tremendous ethnic diversity of the entire Caucasus area combined with the long history of unstable political geography means that other multi-ethnic countries in the region may be at risk for similar outbreaks of internal armed con ict, followed by demodernization and resurgent P. vivax malaria. Recent research has revealed that ethnic violence and other intra-state con icts now outnumber traditional nation-state con icts by a substantial margin in many parts of the world (19). Researchers should be aware that these aggregate changes in global con ict patterns could generate new outbreaks of preventable infectious and vector borne diseases, even in temperate regions that have achieved a modern health and mortality pro le for many decades.

Consent for Publication
Not applicable. This research paper does not contain images of individuals or qualitative interview information from any individual research subjects.

Availability of Data and Materials
Data for Figure 1 was acquired from the Electronic Repository of Russian Historical Statistics (RISTAT) from the International Institute of Social History. Data was acquired from the RLC and Regional Boundary for the Former Soviet Union dataset. The dataset was derived from state and  Soviet administrative boundaries and malaria prevalence per 100,000 population in the Caucasus region before the Soviet malaria eradication campaign, 1922. The Volga River drainage area (illustrated in red) had the highest rates in the region. Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.  Map detailing density of malaria cases and refugee settlements on the periphery of the main con ict zone in Nagorno-Karabakh, 1991 (NGK, highlighted in yellow border). Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors. Topographic wetness index for present-day Armenia, Azerbaijan and the contested Nagorno-Karabakh region (outlined in yellow). This map indicates the level of water run off that collects on the land surface. Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.