The uprising of German cockroaches across Dhaka city

Last June, Dhaka city was shocked to hear about a tragic incident in the Bashundhara Residential Area. 

Two children, 15-year-old Shayyan Mobarat Zahin and 9-year-old Shahil Mobarat Zayyan died from pesticide poisoning. Family members told the media that pest control service staff sprayed pesticide at the family's apartment. 

The incident was a glaring example of how city dwellers have been suffering from the invasion of pests like cockroaches and rely on pest control services for solutions.

Pest control service providers in the city said more than 80% of apartments in the city have been infested with cockroaches. This issue, especially regarding German cockroaches, is increasing fast and poses a serious threat to the health of human residents.  

All the German cockroaches' men 

Cockroaches are nothing new in the city. In the past, inch-size American cockroaches were mostly found in flats, restaurants, markets and hospitals in the city. However, over the last decade, the number of American cockroaches has decreased significantly. 

On the other hand, the number of very small German cockroaches which are commonly known as Chinese cockroaches has increased to such a degree that it has become a serious problem.

They are often found in all areas of the kitchen, and they are so small that they can enter covered food pots through the smallest gaps. The small brown-coloured cockroaches can spread throughout a flat and rapidly become a problematic infestation.

Liton Miah has been actively working in pest control services in the city since 2003. He said that his company Rajdhani Pest Control received more than five phone calls for cockroach control per day.

Over the last 20 years, he said that he had provided pest control services to more than 5,000 households, hospitals, restaurants and hotels in Dhaka.   

"I think now more or less 80% of houses in the city are infested with small-sized German cockroaches," said Liton Miah. "People call us in when they find it difficult to control them any longer."

Zia Uddin, the owner of Noha Pest Control Service, another pest control service provider in the city also said that around 80% of households are now infested with German cockroaches.   

Zia Uddin, working in the pest control service for the last nine years, has worked for more than 500 flats in the Dhaka city area. He stated that the population of German cockroaches had significantly increased during this period. 

Pest control service providers point to a shift: from the invasive infestation of American cockroaches to German cockroaches. These are also the two primary types of cockroaches in Dhaka city, according to them. 

"Now the number of American cockroaches has come down to a great extent. It has been now rare," said Zia Uddin. He believes the reason behind the decline of American cockroaches is the use of pesticides by different pest control services over the years. 

"Now the German cockroaches are dominating the Dhaka city homes, restaurants, hotels and hospitals," Zia Uddin said, adding, "German cockroaches are now making city dwellers' lives hell." 

They believe that the worst conditions are seen in the kitchens of restaurants. With a few exceptions, most of the restaurant kitchens are infested with German cockroaches.  

How have they come home?

Cockroaches have always been in people's homes but the influx of German cockroaches happened due to increased foreign travel as well as increasing importation of goods into the country.

Additionally, German cockroaches don't only come from Germany however, they can arrive from many different countries in Bangladesh. 

"Now more and more people go abroad as a result when they come to Bangladesh, some German cockroaches come with the luggage," explained Zia Uddin, "Sometimes, the luggage is kept in the luggage room or the store room of the airport or the aircraft. A couple or so of cockroaches come with luggage."

He also said that when traders import onions, gingers and garlic, the insect arrives with these goods. The warehouse of the imported goods is a haven for cockroaches because warehouses can remain unclean for years. Grocery shops are also a breeding ground for cockroaches. The pupa, larva or eggs can stick to garlic, ginger and onions. 

These goods arrive at the grocery shops and then finally enter people's homes. 

"Sometimes you will find blackish marks on onions, these are sometimes pupa or larva," said Zia Uddin, "You will have to keep it clean."

Serious threat to public health 

German cockroaches are dangerous pests in any environment, making sanitation imperative in houses, restaurants and hospitals. 

The National Institute of Preventive and Social Medicine and Sir Salimullah Medical College jointly conducted a study titled "Cockroach Associated Foodborne Pathogens: Distribution and Antibiogram" in 2018. 

Cockroaches are among the most common pests in public dwellings and health facilities. They are considered potential carriers and transmitters of human diseases. In hospitals, cockroaches are the possible vector of nosocomial infection, especially for the transmission of drug-resistant bacteria.

The study aimed to identify the major cockroach species, isolate common foodborne pathogens from cockroaches and determine the antibiotic susceptibility pattern of isolated bacteria. 

This study was conducted on 450 cockroaches captured from (150 hospitals, 150 restaurants and 150 houses) in Dhaka city from July to December 2014. 

The study found all (100%) cockroaches were identified as Blattellagermanica or German cockroaches. The study showed that all 100% cockroaches carried bacteria, while the carriage rate of fungi and parasites were 28.2% and 3.7% respectively.

"Cockroaches are potential sources of pathogenic microorganisms including multi-drug resistant bacterial strains, which could be a major threat to public health," reads the study. 

The study recommends effective preventive and control measures are required to minimise cockroach-related infections.

A 2023 study titled "Antibiogram and MDR Pattern of the Bacterial Isolates from German Cockroaches (Blattella germanica L.) at RMCH, Rajshahi, Bangladesh" carried out across three wards at Rajshahi Medical College Hospital (RMCH) revealed that cockroaches are capable of transporting and transmitting germs, leading to the development of antibiotic resistance and multi-drug resistance in patients. 

This concern has garnered significant attention, with the World Health Organisation (WHO) cautioning about the alarming increase in antibiotic resistance worldwide. 

How to get rid of it

There are two ways to get rid of the infestation of cockroaches in the city. The first is to keep the kitchen neat and clean and the second is to call in pest control service providers. 

Unclean kitchens tend to see more German cockroaches than clean ones. Pest control service providers also said that city dwellers can get rid of German cockroaches if they can keep their kitchens neat and clean.  

"An unclean kitchen is the heaven for the cockroaches. If you can keep the kitchen neat and clean. you will never have to worry about cockroaches at all," said Zia Uddin. 

"Some kitchens are garbage – as a result, cockroaches make houses in those kitchens," said Zia Uddin. On the other hand, "There are many people who keep their kitchen neat and clean as a result, they rarely face cockroaches."  

People can also bring in pest control service providers to get rid of the cockroaches with poison. In that case, the price of pest control for cockroaches can be between Tk2,500 to Tk3,500. 

"All people cannot spend the money to bring in pest control service providers. In that case, they should keep their kitchen neat and clean," said Zia Uddin.  

He added that cockroaches love to eat oily food left in the kitchen but rotten food is what they like the most. "If it is a chicken fry," said Zia Uddin, "They will eat to their heart's content". 

He also said that the city dwellers will have to plug up the holes in their rooms so that no insects can enter. At the same time, they will have to be careful while buying onion, ginger and garlic.  

"If you buy eggs, never bring the eggs with its case. You will have to bring eggs separately, Cockroaches live in the cases of the eggs," said Zia Uddin, adding that pupa, larva and egg will stick to the case.