A clinical profile and factors associated with swine flu patients at tertiary health care centre

 

Sanjay Pandharinath Patil¹, Janrao Bhaurao Rajput^2*

 

¹Assistant Professor, ²Associate Professor, Department of Medicine, Dr. Ulhas Patil Medical College and Hospital, Jalgaon, Maharashtra, INDIA.

Email: drrajputjt@gmail.com

 

Abstract              Background: Swine flu (Swine Influenza) pandemic of 2009 was started by swine origin Influenza A virus subtype H1N1 virus strain. Pregnant individuals, children under 2 years of age, young adults, and individuals with any immune compromise are likely to have a worse prognosis. Although the basic determinants of swine flu transmission are common, the magnitude and nature of these factors vary from community to community. Amis and objectives: To study the clinical profile and factors associated with Swine flu patients reporting at the tertiary health care centre. Materials and Methods: In the present retrospective descriptive, record-based study all the cases of suspected Influenza-like illness attending the study institute during the study period were selected and were investigated further. The diagnosis of h1n1 influenza A (swine flu) was confirmed by RT-PCR or culture. A predesigned semi-structured Proforma was used to collect details such as socio-demographic details, detailed address, clinical data of patient. The collected data was entered in Microsoft excel and was analysed and presented with appropriate tables and digraphs. Results: Out of total 523 patients presented with influenza-like illness 54 patients were confirmed cases of h1n1 influenza A (swine flu) by RT-PCR or culture. Majority of the patients were between the age group of 21-30 and 31-40 years of age (29.63% and 25.93% respectively). The proportion of female was 55.56%. 88.89% patients were from urban area. The most common presenting symptom was fever (96.30%) followed by was cough (83.33%) and sore throat (59.26%). Diabetes mellitus (16.67%) was the most common co-existing medical condition, followed by chronic renal failure (3.70%) and pregnancy (3.70%). Bilateral pneumonia was diagnosed on x-ray in 46.30% patients whereas unilateral consolidation was diagnosed in 11.11% patients. Conclusion: Thus we conclude that young age, predominantly male from urban area were most commonly affected by h1n1 influenza A (swine flu). Fever, cough and sore throat the most common presenting symptom whereas Diabetes mellitus was the most common co-existing medical condition. Bilateral pneumonia was diagnosed on x-ray most commonly.

Key Words: Swine flu, H1N1, RT PCR.

 

INTRODUCTION

Swine flu (Swine Influenza) pandemic of 2009 was started by swine origin Influenza A virus subtype H1N1 virus strain.^1,2 Pregnant individuals, children under 2 years of age, young adults, and individuals with any immune compromise are likely to have a worse prognosis.^3-6 Although the basic determinants of swine flu transmission are common, the magnitude and nature of these factors vary from community to community.^1-7 Moreover, disease severity vary from mild illness in one country to much higher morbidity and mortality in another. In addition, virulence of the virus changed over time as the pandemic goes through subsequent waves of national and international spread.⁸ Pandemic influenza A (H1N1) 2009 is a novel strain influenza A virus evolved by genetic reassortment. This virus was first reported in Mexico in April 2009 and rapidly spread to various countries worldwide^9,10. High morbidity (27236 cases) and mortality (981 deaths) have been reported from India¹¹. The unique features of Influenza epidemic are the suddenness with which they arise, and the speed and ease with which they spread. The short incubation period, large number of subclinical cases, high proportion of susceptible population, short duration of immunity, and absence of cross immunity, all contribute to its rapid spread. The fate of the virus during inter-epidemic period is also not known.¹² The Influenza A H1N1 in humans can be a mild illness or in some people it may result in serious, even life-threatening complications such as pneumonia, acute bronchitis, worsening of chronic conditions, respiratory failure and death. People who are increased at risk for developing serious complications of the Influenza A H1N1 included are person under long term therapy, hospitalized patients, and pregnant women¹³.

 

MATERIALS AND METHODS

The present retrospective record based cross sectional study was conducted at the Dr. Ulhas Patil Medical College and HospitalAll the cases of suspected Influenza-like illness attending the study institute during January 2015 to December 2015 were selected and were investigated further. Following case definitions were used to select the study patients.

Influenza-like illness (ILI): Fever (temperature of 100°F [37.8°C] or greater) with cough or sore throat in the absence of a known cause other than influenza^9,14,15.

A confirmed case of h1n1 influenza A (swine flu): An individual with an influenza-like illness with a laboratory-confirmed H1N1 influenza A virus detected by RT-PCR or culture^9,14,15. Throat or nasal swab samples of suspected cases with influenza-like illness (ILI) were collected in Viral Transport Medium and sent to laboratories maintaining cold-chain. RNA was extracted by QIAamp Viral RNA Mini Kit (Qiagen, Germany). RNA of each isolate was tested by separate primer/probe sets for InfA, Universal Swine (swFluA), Swine H1 (swH1) and RNaseP (Applied Biosystems, USA) as per the CDC real-time RT-PCR protocol (ABI Step One Plus RT-PCR instrument – Applied Biosystems, USA)¹⁶. A predesigned semi-structured Performa was used to collect details such as socio-demographic details, detailed address, clinical data of patient (sign and symptoms, co- morbid condition), diagnostic findings of influenza testing, treatment history (use of ventilator), drug details (oseltamivir received or not), outcome details and details of current pregnancy if pregnant. The collected data was entered in Microsoft excel and was analysed and presented with appropriate tables and digraphs.

 

 

 

 

RESULTS

Table 1: Socio Demographic Characteristics of Influenza A H1N1 cases

It was observed that total 523 patients presented with influenza-like illness out of them 54 patients were confirmed case of h1n1 influenza A (swine flu) by RT-PCR or culture. It was observed that out of total 54 cases majority of the patients were between the age group of 21-30 and 31-40 years of age (29.63% and 25.93% respectively). The proportion of female (55.56%) was more as compared to male (44.63%). It was seen that 88.89% patients were from urban area whereas remaining 11.11% were from rural area.

 

Table 2: Distribution according to presenting symptoms

Various presenting symptoms were observed among the patients. The most common presenting symptom was fever (96.30%) followed by was cough (83.33%) and sore throat (59.26%). Dyspnoea was observed in 44.44% and myalgia in 24.07%.

 

Figure 1: Distribution according to presenting symptoms

 

Table 3: Distribution according to associated co-morbidities

Diabetes mellitus (16.67%) was the most common co-existing medical condition, followed by chronic renal failure (3.70%) and pregnancy (3.70%). Other co-morbidities include stroke, seizure and malignancy.

 

Table 4: Distribution according to Chest X-ray findings

Bilateral pneumonia was diagnosed on x-ray in 46.30% patients whereas unilateral consolidation was diagnosed in 11.11% patients. Bilateral hilar enlargement was seen in 3.70%. Normal x-ray was observed in 38.89% patients.

 

DISCUSSION

Influenza spreads through droplets from infected individuals while speaking, coughing or sneezing. Non human influenza spreads from respiratory or gastrointestinal tracts of infected hosts. Flu can occur throughout the year, but peak occurrence is in the winter months ⁹. Flu epidemics occur every 6 to 10 years, usually due to antigenic shifts which expose the population to strains to which it has not been exposed previously^15,17. In the present study patients with influenza-like illness with a laboratory-confirmed H1N1 influenza A virus detected by RT-PCR or culture were selected. Out of total 523 patients with influenza-like illness; 54 patients were confirmed case of h1n1 influenza A (swine flu). It was observed that out of total 54 cases majority of the patients were between the age group of 21-30 and 31-40 years of age (29.63% and 25.93% respectively). Thus majority of the patients affected were young in present study. The findings were comparable with findings observed by Himanshu R et al¹⁸, Jagannatha Rao SR et al¹⁹, Chaudhari AI et al¹³ and Asmita A. Mehta et al²⁰. The proportion of female (55.56%) was more as compared to male (44.63%). Rajesh et al²¹ also found that half of the patients (56.3%) were females. Chaudhari AI et al¹³ and Balaganesakumar S R²² also observed similar findings. It was seen that 88.89% patients were from urban area whereas remaining 11.11% were from rural area. Chaudhari AI et al¹³, Asmita A. Mehta et al²⁰ and Rajesh et al²¹ also observed more cases form urban area as compared to rural area. It has been observed that Influenza A H1N1 cases were reported more from the urban area than rural area. The reason behind it is that; the dense population in urban area favoring spread of virus infection. Attack rates are also high in close population group. The most common presenting symptom was fever (96.30%) followed by was cough (83.33%) and sore throat (59.26%). Dyspnoea was observed in 44.44% and myalgia in 24.07%.  Diabetes mellitus (16.67%) was the most common co-existing medical condition, followed by chronic renal failure (3.70%) and pregnancy (3.70%). Other co-morbidities include stroke, seizure and malignancy. Almost similar result were observed in study carried out by H Rana et al¹⁸, Ketan K Patel et al,²³ Chaudhari AI et al¹³ and Asmita A. Mehta et al.²⁰ Bilateral pneumonia was diagnosed on x-ray in 46.30% patients whereas unilateral consolidation was diagnosed in 11.11% patients. Bilateral hilar enlargement was seen in 3.70%. Normal x-ray was observed in 38.89% patients. Similar findings were also observed by Asmita A. Mehta et al²⁰. Bilateral patchy infiltrates at time of admission, was another risk factor associated with need of mechanical ventilation or mortality which was diagnosed on x-ray. Bilateral pneumonia on chest X-ray might be due to bacterial pneumonia, acute respiratory distress syndrome or progressive viral pneumonia.

 

CONCLUSION

Thus we conclude that young age, predominantly male from urban area were most commonly affected by h1n1 influenza A (swine flu). Fever, cough and sore throat the most common presenting symptom whereas Diabetes mellitus was the most common co-existing medical condition. Bilateral pneumonia was diagnosed on x-ray most commonly.

 

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