European Journal of Cardiovascular Medicine

The most common virus transmitted to people by mosquitoes is dengue. A dengue virus infection can result in a broad range of clinical symptoms, from "Dengue fever" (DF), a mild febrile sickness, to severe dengue that manifests as dengue hemorrhagic fever or dengue shock syndrome (DHF/DSS). Dengue virus belongs to the Flaviviridae family of viruses, genus Flavivirus. The family Flaviviridae is a member of the Arbovirus (an arthropod-borne virus); Togaviridae and Bunyaviridae are additional Arbo virus families. They live in the wild by spreading their infection to vulnerable hosts by specific mosquito species, tics, and sand flies. They are the cause of tick-borne encephalitis, yellow fever, west nile fever, and Japanese encephalitis. In 2003, Lindenbach and Rice.

There are four serotypes of dengue virus: DEN-1, DEN-2, DEN-3, and DEN-4. While all four of them Although serotypes share comparable antigens, their differences are sufficient to provide cross-protection for a brief period of time. Lifelong immunity to the viral serotype is conferred by infection with any one serotype (WHO 1999). 2. They have antigens that cross-react with viruses belonging to the same genus, including those that cause yellow fever, Japanese encephalitis, and west nile. Several genotypes have been identified for every serotype by nucleotide sequencing. There are 3 genotypes in DEN-1, 6 in DEN-2, 4 in DEN-3, and 5 in DEN-4.There is a single non-human genotype present in primates under DEN-2 and DEN-4. Different Aedes mosquito species are responsible for the transmission of the dengue virus from person to human. Dengue is spread by arthropods, specifically female members of the genus Aedes. They sting people during the day. Ae. aegypti is able to spread dengue either right away (by switching hosts when feeding is halted) or after the virus has multiplied in the salivary gland for eight to ten days during incubation. The mosquito host is contagious for life after infection. Dengue virus transovarian transmission has been observed, however its epidemiological significance has not been determined.

One of the main viral diseases spread by mosquitoes, dengue affects an estimated 100 million people annually globally. Dengue has grown to be a serious worldwide public health issue in recent years. It is estimated that over 2.5 billion individuals (or 40% of the world's population) are at risk of infection. These people primarily reside in urban areas of tropical and subtropical countries. According to WHO estimates, there are between 50 and 100 million infections annually, with 5 lakh DHF cases and 22,000 deaths—mostly in children. Although dengue is prevalent in over 100 countries, the majority of infections are recorded from the western Pacific and South-East Asia regions. (WHO 2013) In India, dengue has been reported to be on the rise. The past forty years have seen a significant increase in the disease's geographic distribution, number of cases, and severity due to increasing urbanisation and the expansion of transport infrastructure in various regions of India, which has resulted in a severe shift in the environment. Although the benign and self-limiting type of DF, known as DHF, has been increasingly common in recent years, it has been known to be endemic in India for over 20 years. Reports of dengue epidemics in both urban and rural populations have been made often from various regions of the nation. Eighty percent of dengue virus infections are asymptomatic or exhibit modest symptoms like a simple fever. Others have a higher percentage of severe sickness (5%) and a smaller percentage of life-threatening disease (Reiter 2011).

Dengue often begins as a self-limiting acute fever sickness and progresses to a key defervescence period, during which time patients may get well or develop into a severe form. Hemodynamic abnormalities, increased vascular permeability, hypovolemia, hypotension, and shock are indicative of severe illness. In all situations, thrombocytopenia and platelet dysfunction are prevalent and have an impact on the clinical result. DENV-associated thrombocytopenia has been explained by a variety of processes, including peripheral platelet degradation and bone marrow suppression. Research has demonstrated bone marrow stromal cells or hematopoietic progenitors infected with DENV. Furthermore, since platelets interact with immune cells, endothelial cells, and/or DENV, anti-platelet antibodies would play a role in peripheral platelet death. Whether platelets contribute to the viral spread is yet unknown. The working mechanics of platelet dysfunction and thrombocytopenia in DENV infection has been covered in a number of academic publications. Platelets have been regarded as "immune-like effector cells" because they promote the release of cytokines, chemokines, and inflammatory mediators, which contribute to the inflammatory and immunological response. It has also been considered how platelets may be affected by plasma leakage, given that thrombocytopenia is linked to worse clinical outcomes and increased mortality.

The study included 100 patients aged ≥ 14 years with dengue virus infection admitted to the department of Medicine, SCB Medical College, Cuttack between January 2018 to December 2019.

 Inclusion Criteria

All suspected cases of dengue as defined under National Vector Borne Disease Control Programme (NVBDCP), Govt. of India were evaluated and tested for enzyme-linked immunosorbent assay (ELISA) based NS1 antigen and IgM capture ELISA (MAC ELISA).

Government of India recommends use of ELISA based antigen detection test (NS1) for diagnosing the cases from 1st day to 5th day and antibody detection test IgM capture ELISA for diagnosing the cases after 5th day of onset of disease for confirmation of dengue infection.

 Exclusion Criteria

1. Patient with leukaemia
2. Patient with ITP
3. Patient with Aplastic anaemia

Statistical Analysis

 All statistical analysis was performed by Graphpad prism 5.01. The statistical analysis was done using the Fischer’s exact test and student’s unpaired t-test for significance of difference in proportions and means between two groups respectively. Mann- Whitney test was used for significance of difference in means for non-Gaussian data. A P value <0.05 was considered as significant.

Table – 1: Age Distribution Of Patients With Dengue Infection

The maximum number of cases were seen in the age group of 31-40 years i.e. 28 (28%) followed by 21-30 years 26 (26%). The mean age of patients in our study was 38.62 years with a range of 17 to 68 years.

TABLE – 2 :  Sex Distribution Of Patients With Dengue Infection

Total numbers of males were 68 (68%) while females were 32 (32%) in our study. Male to female ratio was 2.1:1. The males were predominantly infected with dengue virus.

TABLE – 3: Dengue Serological Test In Study Group

Out of 100 cases, only 5 cases were dengue IgM antibody positive. Rest 95 cases were positive for dengue NS1 antigen.

Table – 4: Hematological Profile Of Dengue Patients During Hospital Stay

Out of 100 patients 27 patients had Hb level <10 g/dL, 11 patients had leukopenia i.e. TLC <4000 and 1 patient had leukocytosis i.e. TLC >11,000. 29 patients out of all cases were found to have thrombocytopenia i.e. TPC <1,00,000 by direct smear during hospital stay and 9 patients had raised hematocrit i.e. >45.

Table – 5: Renal Function Parameters Of Dengue Patients

Out of 100 patients 9 patients had presence of albumin in their urine, 7 cases with pus cell and 1 patient had RBC in urine. 22 out of 100 cases were found to have increase Sr. creatinine level i.e.>1.2 and increased sr. urea i.e. >40 were seen in 30% cases.

TABLE – 6: Liver function parameters of Dengue patients

Out of 100 patients 12 patients had raised total bilirubin i.e. >2.5 and there was found to have raised direct bilirubin level i.e. >1.2 in 15 cases. Features of hepato cellular dysfunction like raised liver enzymes like SGOT and SGPT are raised >3 times of upper limit of normal value i.e. >120, was seen in 21 cases for each. Out of 100 cases 17 cases were found to have raised ALP level and only 1 case had deranged PT/INR. Out of all cases 1 case had presence of ascites.

Table – 8 : Day Wise TPC By Both Automated Counter And Manual Method In Study Group

 Out of 100 patients, total 25 patients presented with thrombocytopenia i.e. TPC <1 lacs as per automated counter method in comparison to 28 patients with TPC < 1 lacs as per manual method on first day of illness. Out of all patients with thrombocytopenia on day 1, 6 patients had TPC < 20,000 by manual method as comported to 4 patients by automated counter method.

Subsequently on day 2 & 3, total 22 & 10 patients respectively presented with thrombocytopenia i.e. TPC < 1 lacs as per automated counter method. Whereas by manual method only 20 & 4 patients presented with thrombocytopenia respectively. No patients had TPC < 20,000 on day 2 & 3 by either methods.

The total platelet count is a worry for dengue patients, treating clinicians, and the general population (TPC). So much so that treating physicians' obsession with platelet counts is sometimes referred to as their "Dengue Panic Syndrome." Without a doubt, the following elements should be taken into consideration: risk factors, concomitant disease, warning signs and symptoms, haematocrit, and stages of the illness (febrile, critical, or recovery). Even though TPC is given far greater priority now than it was in the past, its significance cannot be understated. When a patient's platelet count drops during defervescence and their haemoglobin level rises, it frequently indicates a critical path. 

The discrepancy between TPC reports produced manually and by auto-analyser is another major source of worry. A blood sample stored over an extended period of time will clot. The auto-analyzer will identify a cell based merely on its size. Depending on its size, a platelet cluster can be identified as an RBC or as another sort of cell. Consequently, the auto-analyser's TPC will produce a smaller count. Nevertheless, these clots may be seen by looking at a direct smear slide, and platelets only clump together when their overall count is sufficient and they are in sufficient quantity to approach each other while circulating.
However, there's a danger that some cells will deteriorate if the blood sample is stored for an extended period of time. The auto-analyzer will identify these anuclear, fragmented pieces of the other cells as platelets, which will result in increased TPC.

The current study was conducted from January 2018 to December 2019 at the SCB Medical College and Hospital in Cuttack. Thousands of patients with dengue are admitted annually to this top medical facility in Eastern India. Patients from other states come here as well since the treatment is completely free, including the ICU fees. This study was a prospective observational design that aimed to track TPC on a daily basis, compare TPC using automated counter technique and manual way, identify variables influencing TPC, and correlate TPC with various organ involvement and patient outcome.

The age group of 31–40 years old saw the greatest number of patients in the research (28%), followed by 21–30 years old (26%). The patients' ages ranged from 17 to 68 years old, with a mean age of 36.62. (Table 1). Neelakantha S. Patil et al. conducted a retrospective observational research in a tertiary care hospital, and 36.63% of the 1111 patients were in the 20–29 age range. Thirty percent of the patients in a Lahore research came from the 20–29agerange.

These support our conclusion that younger patients are more frequently engaged. Similar age group involvement has also been documented by Somia Iqtadar et al. and Trung et al. Given that all of these trials are conducted on hospitalised patients, older participants are anticipated to  surpass those in the younger age range. Because all comorbid illnesses worsen with age and age itself is a risk factor, there is a greater chance of a critical course of dengue fever, which may require hospitalisation. The younger age group's involvement in all of these research likely reflects young people's attitudes, which increase the danger of mosquito bites by sleeping without mosquito nets, covering extremities incorrectly with fabric, and not applying insect repellents.

surpass those in the younger age range. Because all comorbid illnesses worsen with age and age itself is a risk factor, there is a greater chance of a critical course of dengue fever, which may require hospitalisation.
The younger age group's involvement in all of these research likely reflects young people's attitudes, which increase the danger of mosquito bites by sleeping without mosquito nets, covering extremities incorrectly with fabric, and not applying insect repellents.

Haematological abnormalities associated to platelet and endothelial dysfunction that are typically seen in severe dengue include thrombocytopenia, coagulopathy, and vasculopathy. Previous research has indicated that one of the causes and effects of DIC may be an imbalance between the clotting and fibrinolysis systems. A small percentage of individuals experiencing severe or protracted shock may have substantial abnormalities. These abnormalities, when combined with severe thrombocytopenia and the downstream consequences of acidosis and hypoxia, can lead to massive bleeding and real DIC. DIC is mostly brought on by the release of TF, and in dengue patients, it can activate the PAR membrane receptor on circulating monocytes and vascular endothelial cells, creating an important connection between inflammation and coagulation. Children with DSS had minimally altered coagulation screening test findings, minimally clinically significant bleeding, and substantial anomalies in each of the coagulation cascade's main routes. The degree of shock is correlated with low levels of proteins C, S, and antithrombin in the blood, which are probably caused by these proteins leaking through the vascular endothelium. Increased TF, thrombomodulin, and PAI-1 levels indicate endothelial, platelet, and/or monocyte activation and might be a secondary reaction to the dengue virus directly triggering fibrinolysis.

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