Mosquito Economics in Laboratory : A Retrospective Study in a Tertiary Care Hospital in India

Background: Malaria, Dengue and Chikungunya are the major mosquito transmitted febrile illness in India. The retrospective study shows the three year trends in the laboratory testing for these diseases. These mosquito borne fever occur in the post monsoon period from late August till October every year. Methods: We collected data from test ordered for three mosquito borne diseases for past three years from laboratory software. Descriptive statistical analysis was done. Result: The total tests ordered for Malaria in the three year period were 4224, 5433 & 2360 for the year 2015-17, for Dengue 3978, 5957 & 2360 and for Chikungunya 258, 2525 & 170 respectively. The percentage positivity for malaria over three year period was 1.78% for 2015, 2.04% for 2016 and 1.99% for 2017. For Dengue it was 50.25% for 2015, 30.6% for 2016 and 14.76% for 2017. Chikungunya had higher percentage positivity in 2016 which was 28.67%, 13.18% in 2015 and 12.94% in 2017. The demand for tests was maximum in post monsoon period from September till October for the entire three vectors borne illness every year. Conclusion: The magnitude of increased workload on diagnostic facilities poses a challenge to developing countries. The study will enable the policy makers in taking rationale scientific decisions to issues of sanitation, cleanliness and hygiene in general, population and also on manpower management in diagnostic services so as to deliver quality health care facilities in the need of hour.


Introduction
Vector -borne diseases are illness caused by pathogens and parasites in human population. In India vector borne diseases such as Malaria, Dengue and Chikungunya present as febrile illness and are leading cause of morbidity. On one hand our country suffers from burden of this vector borne disease which is related to sanitation, hygiene issues and availability of safe drinking water on the other hand there is emergence of non communicable disease linked to life style changes [1]. We have to make a balance in allocation of resources among diseases of developing and developed country. Half of India's disease burden in any financial year is attributed to these seasonal diseases [2].
In India there is wide distribution of anopheline vectors but they transmit primarily two Plasmodia species named P. Vivax and P. Falciparum. According to the World Health Organization (WHO) India alone contributed to 76% cases of malaria from south East Asia in 2014 [3]. The world malaria report published in 2014 showed that in India 22% population lives in high transmission areas (>1 case per 1000 population), 67% live in low transmission areas (0-1 case per 1000 population) and 11% live in malaria free areas (zero case) [4]. Malaria comprises the chunk of vector borne disease; according to the Directorate of the National Vector Borne Disease Control Program me (NVBDCP), about 95% of our population resides in malaria endemic zone [5].
Dengue fever is a mosquito borne viral disease with four virus serotypes (DEN-1, DEN-2, DEN-3 and DEN-4) that are present in Asia, Africa and America [6,7]. It has become a significant health problem due to expanding geographic distribution with climate change and gradual evolution from an epidemic with long year's interval into an epidemic with seasonal trend [8,9]. Vector development and survival rates are affected by temperature, precipitation and humidity although the associations of environmental factors are not consistently described in literature [10,11].
Chikungunya on the other hand is a flavi viral infection transmitted to humans by Aedis aegypti [12]. It is relatively unknown in Indian population till it appeared in epidemic propotions in 2006. The word Chikungunya originated from the word Kungunyala (meaning that which bends up) as the patients suffering from Chikungunya develop a stooped posture because of severe arthritis affecting feet, ankles, hands and wrists [13].
The entire three vector borne viral fevers have high incidence in late monsoon where they pose a major health problem. There is paucity of data on the economic burden on the household and the expected cost of illness. This paper attempts to retrospectively analyze the seasonal and yearly trends in the laboratory workload due to these vector borne diseases so that effective preventive as well as curative measures can be taken to save precious lives.

Materials and Methods
We conducted a retrospective study in the department of Pathology & Transfusion Medicine at our center over the period of two and a half years from 2015 till September 2017 to analyze the trend in testing for these mosquito transmitted fever. The study population were all patients who came to the department for any of the three vector borne febrile illness; Malaria, Dengue and Chikungunya. The data was collected from the laboratory software and descriptive statistics was applied. Patients who had undergone twice testing for the specific disease were considered as single case and no duplication of patients was done in the study.

Result
The retrospective study for three vector borne disease -Malaria, Dengue and Chikungunya was done in our department. The test ordered for malaria, dengue and chikungunya in the year 2015 were 4224, 3978 and 258 respectively (Table-1 , Fig-1). There was increase in the number of tests ordered in 2016 where the figures for three vectors borne disease stood at 5433, 5957 and 2525 respectively (Fig-2). In 2017, till September the test numbers stood at 2360, 2588 and 170 respectively (Fig-3). The percentage positivity for malaria over three years was 1.78% in 2015, 2.04% in 2016 and 1.99% in 2017 (Table-1). The positivity for dengue was 50.25% in 2015, 30.60%in 2016 and 14.76% in 2017 (Table-1). Similarly for chikungunya the percentage positivity was 13.18%, 28.67% and 12.94% in three consecutive years under study (Table-1). The number of test ordered showed a steep increase in August month rising to peak in September and October and then falling in November (Figure-4, 5&6). More than 50% of the tests ordered for specific vector borne disease were recorded in the three month span from August to October (Table-2       In the year 2017, there is slight decrease in the test numbers and percentage positivity which might be attributed to late extended rainy season and partly due to awareness among public relating to hygiene and sanitation. Malaria is one of the serious public health problems across globe amounting to 400-500 million cases and more than  [14]. There are several factors responsible for resurgence of malaria including, growth of human population, change in land usage, changes in temperature, rainfall , humidity and immunity levels. In India more than 973 million persons are exposed to malaria and in 1998 an estimated 577,000 disability adjusted life years (DALYs) were lost due to malaria [15]. Similarly the arboviral diseases like chikungunya and dengue are also affected by climate change and have high propensity to occur in post rainy season. Chikungunya appeared in India in 1963 but it reemerged in 2005 and since then it has spread with more than a million cases reported [1,16,17]. As the activity, distribution of mosquito and its ability to transmit virus is highly dependent on temperature and precipitation, we observe continuous peak resurgence every year for these vector borne diseases8.Dengue too has been a significant health problem as there has been repeated outbreaks in India since 1960 [18].
Our study shows that not only physicians but also laboratory services should be prepared to accommodate rising work flow in months of increased demand, to provide quality hassle free services. In this three year study, there was a rapid increase in number of dengue cases was observed in 2016 compared to the previous two years. The maximum number of dengue cases was seen in the month of September (Fig-5) indicative of an active viral transmission during monsoon and post-monsoon period, this finding was similar to other studies by Gupta E et al [19] and Ukey PM et al [20].
Our study depicts the seasonal variation in workload of three tests conducted by clinical laboratory. These tests for vector borne disease follow a seasonal pattern with increased work starting from August and reaching peak by mid September-early October and then declining by mid November. The laboratory staffing has a direct relationship on patient outcome and error rates in laboratory [21]. Our findings along with other published work in literature should provide evidence based information to enable directors of clinical laboratories in making objective decisions on restructuring the workforce. In a developing country like India where economic constraints prevail and laboratories generally suffer from budget cuts there is need for objective decisions so as to maintain the delivery of quality laboratory services throughout year. The workload trend emphasize the need of optimized staffing, right staff with right skills, in the right place and at the right time.

Conclusion
We have made an attempt to describe major seasonal vector borne disease and more studies are required for evaluation of factors related to seasonal variations. There is need of more public awareness campaigns , role of print media, electronic media and other means to inculcate value of sanitation, hygiene and cleanliness in order to restraint the spread of seasonal illness.