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The evolving complexity of malaria trends in the endemic region of Khanh Vinh district, Khanh Hoa province, 2023-2024 (Part 2)
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IV. CHALLENGES AND TECHNICAL BARRIERS IN CONTROL AND ELIMINATION OF MALARIA The malaria outbreak in Khanh Vinh district between July 2023 and July 2024 has presented several alarming trends and risks that demand urgent attention due to the high potential for disease spread and unpredictable complications: - Unprecedented Proportion of P. malariae oThe P. malariae species accounted for 52.8% of cases (104 out of 197), surpassing the two traditionally dominant species, P. falciparum (14.7%, 29 cases) and P. vivax (31.5%, 61 cases). oSuch a high proportion of P. malariae has not been reported in the Greater Mekong Subregion since 1961 or in Viet Nam, where previously only 3-5 cases were recorded annually. - Increased Severity of P. malariae Cases oAlthough historically benign, P. malariae has led to six severe malaria cases in the past two years, treated at Khanh Hoa Tropical Hospital and Ho Chi Minh City Tropical Diseases Hospital. oMost cases involved multi-organ failure, with patients initially showing no symptoms or having parasitemia below detection thresholds of microscopy and rapid tests. - High Rate of Asymptomatic Malaria oOver 76% of P. malariae and P. vivax patients exhibited no symptoms at the time of blood sample collection for diagnosis by rapid diagnostic tests or Giemsa-stained blood smears. - Low-Density Parasitemia Detected via Molecular Tools oAdvanced molecular biology techniques (e.g., nested-PCR, ultra-PCR) detected malaria in 38 of 7,256 individuals with very low parasite densities. oThis suggests a substantial undetected reservoir of asymptomatic cases, acting as an "iceberg" of infection, posing a risk of sustained disease transmission. - Extended Persistence of P. malariae and P. vivax oThese pathogens can persist in human tissues for decades, serving as long-term reservoirs for transmission. - Unusual Molecular Markers in P. malariae oPreliminary analysis of clinical isolates has revealed unique molecular markers and mutations not seen in other parts of the Greater Mekong Subregion. - Late-Stage Parasite Detection oOver 86% of diagnosed cases had schizont-stage parasites (linked to severe malaria) and gametocytes, indicating delayed detection and poor healthcare-seeking behavior. - Shift in Vector Populations oChanges in the distribution of primary and secondary Anopheles vectors have been observed, altering transmission dynamics in the district. - High-Risk Mobile Populations oOver 95% of malaria patients in the district belong to transient or mobile populations engaged in activities such as forest work, temporary campsite setups, overnight stays, or occupations like breeding fish, harvesting wood, collecting honey, hunting wild animals, gathering Dac seeds, bamboo shoots, orchids, or fresh ginseng for sale to traders. - Potential Reservoirs in Primates oThe proximity (32-40 km) of malaria patient clusters to Monkey Island in Ninh Hoa district raises questions about the role of primates as potential reservoirs, though no conclusive evidence has been found. Implications and Urgent Needs These challenges have created a complex epidemiological landscape that threatens to reverse gains in malaria control and elimination in Khanh Hoa province. The outbreak not only jeopardizes public health but also risks undermining the province's economic development and eco-tourism potential. With three malaria parasite species (P. falciparum, P. vivax, and P. malariae) actively circulating and cases becoming increasingly severe, the health sector must urgently address the following priorities: ·Strengthen surveillance, detection, and diagnosis systems. ·Ensure timely and effective treatment and case management. ·Interrupt transmission chains and reduce community spread. ·Accelerate progress toward malaria elimination in Khanh Hoa province. V. CHALLENGES IN PROFESSIONAL AND SOCIO-ECONOMIC ASPECTS - Epidemiological and Environmental Factors oMost malaria cases detected are linked to occupational exposure, such as working in fields, harvesting non-timber forest products, trapping wildlife, or fishing in remote forest areas. These suspected infection sites are often deep in the forest, with difficult terrain, making them challenging to access, manage, and monitor. Many cases are identified passively, only when patients seek care at health facilities. - Infection Sources Embedded in Lifestyle oPathogens persist in forests, fields, and farmhouses, while people?s livelihoods are closely tied to these environments. Cutting off the infection source is extremely difficult, as forest-related activities are essential to their subsistence and cannot be effectively controlled or prevented. - Limited Awareness and Cooperation oAwareness about malaria prevention remains low. Practices such as impregnating bed-nets, consistently using mosquito nets, or employing insecticide-treated hammock covers in the forest are limited. oResistance to blood smear testing, particularly among high-risk groups, hinders timely diagnosis and treatment. - Delay in Seeking Treatment oSome individuals seek care from pharmacies or private facilities when symptoms arise, often delaying proper diagnosis and treatment. This results in disease progression, increasing the risk of severe cases and community transmission. - Significant Rise in Malaria Cases oMalaria cases in the first seven months of 2024 are seven times higher than the same period last year. oKhanh Vinh district has yet to reach its two annual malaria transmission peaks. The potential influx of mobile populations into flood-affected areas and occupations tied to forest activities could further exacerbate the situation. - Reduced Community Immunity oFollowing years of low malaria transmission, community immunity has likely declined, making outbreaks more widespread and severe. - Strain on Resources oOver the past 14 months (July 2023 - July 2024), the high case load and prolonged outbreak have significantly strained the resources of commune health stations, the district health center, the provincial CDC, and other institutions. Human resources, equipment, supplies, and funding have been stretched to their limits. - Outdated Epidemic Control Methods oTraditional methods of epidemic control are proving insufficient to address the unique challenges posed by this unprecedented outbreak. Innovative and effective approaches are urgently needed, particularly for managing P. malariae. - Understanding Local Populations oThe settlement patterns and lifestyles of indigenous ethnic minorities, who are frequently affected by malaria, require further study to improve disease control and prevention strategies. - Tracking High-Risk Groups oThe list of individuals engaging in forest and field-related activities must be continuously updated, considering career shifts and mobility patterns. Notably, many malaria cases occur outside the recognized high-risk groups. - Ineffectiveness of Current Vector Control Measures oCurrent vector control measures are inadequate for fields and forest areas. Strategies such as Targeted Drug Administration (TDA) or Testing and Targeted Drug Administration (TaTDA) could improve diagnostic coverage and facilitate the treatment and elimination of residual malaria hotspots. - Lack of Data on Chemical Effectiveness oData on the effectiveness of residual chemicals on walls and impregnated chemicals used in mosquito nets and hammock covers in endemic areas are unavailable, raising concerns about their efficacy. Addressing these challenges requires a multifaceted and innovative approach. The persistence of malaria in Khanh Vinh district underscores the need for stronger interventions, improved public health strategies, and community engagement to control and eventually eliminate malaria in this region. VI. PROPOSED SOLUTIONS TO PREVENT FUTURE MALARIA OUTBREAKS - Strengthening Surveillance and Early Diagnosis oContinue implementing surveillance activities as per Decision No. 4922/QD-BYT (October 25, 2021) on malaria surveillance and control and Decision No. 3377/QD-BYT (August 30, 2023) on malaria diagnosis and treatment guidelines issued by the Ministry of Health. oEnhance epidemiological investigations, particularly in high-risk areas, villages, and hamlets where malaria patients reside or where new disease foci are suspected. Organize screening activities using Giemsa-stained blood smears or rapid diagnostic tests (RDTs) to identify and treat malaria cases early. - Proactive Vector Control Measures oDevelop and execute plans for insecticide spraying and mosquito net impregnation in the second phase of 2024, following the directives of the Khanh Hoa Provincial CDC. Ensure the malaria control plan for 2024 meets assigned targets. - Directing Local Health Stations oImplement surveillance and control activities per Decision No. 4922/QD-BYT and Decision No. 3377/QD-BYT. oEnhance testing by performing blood smears or RDTs for suspected malaria cases. oStrengthen weekly and monthly surveillance in high-risk groups, including individuals working in forests, fields, and malaria-endemic areas. oDistribute long-lasting insecticide-treated bed nets and hammocks per the RAI3E project guidelines, and ensure widespread use through campaigns. oGuide village health workers to manage mobile populations, conduct household visits, promote malaria prevention measures, and assist in epidemiological surveys and insecticide spraying. oCollaborate with local authorities to monitor mobile migrants and individuals entering forested areas, ensuring timely blood smear testing upon return. - Targeted and Extended Treatment Approaches oConsider mass treatment for at-risk populations or targeted treatment for high-risk groups, as outlined in Decision No. 3377/QD-BYT, when scientifically justified and when the benefits outweigh the risks. Implement such programs with approval from Khanh Hoa Provincial Authorities and technical support from the IMPE-QN. - Ensuring Adequate Drug and Equipment Supply oMaintain a stock of essential antimalarial drugs (e.g., Artesunate, Pyronaridine Tetraphosphate-Artesunate [Pyramax®], Chloroquine Phosphate, Primaquine Phosphate, Quinine Sulfate). oEnsure the availability of diagnostic equipment, including blood smear kits, RDTs, and accompanying tools. Repair or replace damaged equipment promptly and provide training on the proper use and maintenance of medical equipment. - Enhancing Communication and Awareness oSeek funding to produce communication materials (e.g., posters, hoardings) and distribute mobile communication kits equipped with speakers and malaria prevention content for use during field investigations and community outreach. - Capacity Building for Medical Teams oMobilize resources to train medical teams from Provincial CDCs, District Health Centers, Commune Health Centers, and Village Health Workers on surveillance, vector control, diagnosis, and treatment. Enhance skills in community engagement, impregnating bed nets, and spraying residual insecticides. - Improving Living Conditions of High-Risk Groups oProvide mosquito repellents, insecticide-treated single-top nets for farming houses, and other preventive tools for individuals working temporarily in high-risk areas. oAddress broader socio-economic factors, including food security, income stability, and sustainable livelihoods, to improve overall resilience against malaria. - Long-Term Sustainability and Government Support oAdvocate for local governments to prioritize malaria prevention as part of broader community welfare and development programs, ensuring a sustainable approach to disease prevention and control. By implementing these measures, the health sector can strengthen its ability to control and prevent malaria outbreaks effectively, protect high-risk communities, and move closer to eliminating malaria in the region.
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